ALTECH 2017 - Analytical techniques for precise characterization of nano materials

Resume : Tip-enhanced Raman Spectroscopy (TERS) is a nanoscale chemical analysis and imaging method with a spatial resolution of the order of 10 nm. TERS is similar to SERS, and relies on enhancement of the local electromagnetic field in the vicinity of a plasmonic nanostructure that is scanned over a sample by means of a scanning probe microscope, using either AFM or STM feedback. The local enhancement of Raman scattered light is many orders of magnitude, large enough to render monomolecular films spectroscopically visible that would otherwise be optically too thin to be analyzed with conventional vibrational spectroscopy. The working principle and experimental realization of TERS will first be presented. An important advance concerns the production long-lived silver TERS tips that, thanks to the presence of a chemical protection layer, live for many weeks as opposed to the typical lifetime of ≈1 day for bare Ag tips.  Then, applications of TERS to the spatially resolved chemical analysis of molecular nanomaterials, including graphene, 2D polymers, and self-assembled monolayers will be discussed.

Resume : The parallel non-destructive chemical and physical characterisation of materials at the nanoscale is a highly sought-after capability. However, the lack of analytical techniques that can directly probe these structure–property relationships presents a major obstacle to device development. In this work, we present a new method for non-destructive mapping of the morphology, chemical composition and photoelectrical properties with <20 nm spatial resolution by combining plasmonic optical signal enhancement with photocurrent AFM. We demonstrate that this approach offers subsurface sensitivity that can be exploited to provide molecular information with nanoscale resolution in all three spatial dimensions. Such ability to directly measure the impact of structure on optoelectronic function is unique and solves the issue of finding the same location when using a sequence of experiments to obtain different properties. We apply this method to an organic solar cell and show that we are able to correlate local nanoscale composition to photocurrent generation, including the direct identification of impurities within nanoscopic domains of operating solar cells. The multi-parameter measurement approach demonstrated here is expected to play a significant role in guiding the design of nanomaterial-based optoelectronic devices, by opening new possibilities for advanced investigation via the combination of nanoscale optical spectroscopy with a range of scanning probe microscopy modes.

Resume : Novel nanomaterials like semiconductor nanoparticles, 2D materials and devices thereof are of rising interest for plasmonic and optoelectronic applications. The desire for a better understanding of their functional properties calls for analysis tools able to measure them on the nanoscale. This talk focuses on the latest scientific achievements in the field of near-field microscopy using our neaSNOM scattering-type scanning near-field optical microscope. The neaSNOM combines the resolving power of near-field microscopy with the analytical aspects of FTIR spectroscopy to perform imaging and spectroscopy with 10 nm resolution. This technique has already been used in applications such as chemical identification [1], free-carrier profiling [2], or direct mapping of propagating plasmons and polaritons [3,4], providing direct access to the optical properties within the entire mid-IR spectrum. Key information like the local conductivity, intrinsic electron-doping, absorption or the complex-valued refractive index can now routinely be obtained on the nanoscale. As a highly flexible platform, the neaSNOM further supports correlation microscopy e.g. by adding photocurrent nanoscopy [5] or nanoscale Raman (TERS). Refs: [1] F. Huth et al., Nano Lett. 12, 3973 (2012) [2] J. M. Stiegler et al., Nano Lett. 10, 1387 (2010) [3] Z. Fei et al., Nature 487, 82 (2012) [4] E. Yoxall et al., Nat. Phot. 9, 674 (2015) [5] M. B. Lundeberg et al., Nat. Mat. (2016)

Resume : The ability to probe the electrical properties of nanometer-wide semiconducting and metallic lines, as found in the different layers of the front end and back end of line of modern fin field-effect transistors (finFETs), is of the utmost importance. The confined dimensions of these conductive lines indeed impact their electrical conductivity via e.g. sidewall roughness or size-dependent dopant activation/diffusion, while simultaneously making them much more challenging to measure experimentally. On such narrow structures, e.g. conventional four-point probe fails, mostly due to the challenging alignment of the four millimeter-sized and -spaced probes to the nanoscale trenches. As a consequence, little is known of the impact on these properties of the increased surface/volume ratio. In this paper, we evaluate the capabilities of the micro four-point probe technique, as implemented in the fully automated microHALL-A300 tool of CAPRES A/S, for the direct probing of the electrical resistance of narrow Si, Ge, InGaAs and metallic lines. As we demonstrate, thanks to probe sizes and probe pin distances downscaled to a few micrometers, it is possible to measure conductive lines confined to widths down to 20 nm with ~1% precision. Next, focusing on Si, the measured variations in sheet resistance vs line width are interpreted as a surface-state-induced depletion effect, which is confirmed based on numerical simulations and Scanning Spreading Resistance Microscopy measurements.

Resume : Functional metal oxides have a wide variety of technological applications attracting a large interest over the past decade. One particular class of functional metal oxides is represented by transparent conductive oxides (TCOs) that are cornerstone for the development of an emerging area, the transparent electronics. TCOs are an unusual class of materials possessing two physical properties, high transparency and high conductivity that are usually mutual exclusive. For the development of novel TCOs the measurement of both dielectric function and optical bandgap are of high priority and as well the study of their vibrational properties. Optical spectrophotometry and Spectroscopic ellipsometry (SE) are two non-destructive and versatile characterization techniques commonly used for the characterization of optical properties of TCOs. We discuss here the methodology for the accurate determination of both dielectric function and optical bandgap. This requires a complex approach and the benefits and pitfalls of either using optical spectrophotometry or spectroscopic ellipsometry are considered in details. The experimental determination of the optical dielectric function over a large spectral range from UV to Far IR, optical bandgap and vibrational properties inferred from combined approach involved Infrared Ellipsometry, Raman and IR spectroscopy, for several n and p-type TCOs is discussed and results are then compared with theoretical calculations.

Resume : Charge transport in organic semiconductors is strongly dependent on the molecular orientation and packing, such that manipulation of this molecular packing is a proven technique for enhancing the charge mobility in organic transistors. However, quantitative measurements of molecular orientation in micrometre-scale structures are experimentally challenging. Several research groups have suggested polarised Raman spectroscopy as a suitable technique for these measurements and have been able to partially characterise molecular orientations using one or two orientation parameters. Here we demonstrate a new approach that allows quantitative measurements of molecular orientations in terms of three parameters, offering the complete characterisation of a three-dimensional orientation. We apply this new method to organic semiconductor molecules in a single crystal field-effect transistor in order to correlate the measured orientation with charge carrier mobility measurements. This approach offers the opportunity for micrometre resolution (diffraction limited) spatial mapping of molecular orientation using bench-top apparatus, enabling a rational approach towards controlling this orientation to achieve optimum device performance.

Resume : Progress in vibrational spectroscopy methods has offered exceptional advantages for the investigation of structural and molecular properties of nanocomposites. Particularly, the combination of Raman spectroscopy with confocal microscopy allows the rejection of out-of-focus Raman scattering and provides chemically specific information at high spatial resolution. This ability becomes critical for delivering detailed information about the morphology of nanocomposites. This contribution will reveal the advantages of Raman imaging for the quantitative analysis of spatial distribution of nanofillers in thermoplastics. Also, the nature of the interactions between the filler and matrix is characterized using confocal Raman imaging. Raman spectroscopy also brings new insights to the quantification of stress-transfer processes in polyethylene based nanocomposites. The nanocomposites consist of polyethylene as a matrix, and cellulose nanocrystals (CNCs) or multiwalled carbon nanotubes (MWCNTs) as nanofillers. All samples were prepared by melt compounding. The findings based on the Raman method will be discussed in comparison with conventional techniques used for nanocomposites characterization. Acknowledgements The authors would like to thank the EU FP7 funding programme for supporting the work under grant agreement no 604168 (www.newspec.eu). NFI would like to thank to the Ministry of Higher Education (Malaysia) for the PhD scholarship and University of Putra Malaysia for the support.

Resume : In the last years, there has been a considerable interest in the use of nano manufacturing techniques for the fabrication of highly effective substrates for Surface Enhanced Raman Spectroscopy (SERS) to lower the concentration limit of molecular detection down to single molecule. The fabrication of plasmonic nanostructured substrates requires an adequate trade-off between enhancement, for suitable chemical detection level, and reproducibility and uniformity, to guarantee a consistent sensitivity across the surface. Flexible gold-coated silicon nanowires ordered in a matrix represent a promising substrate because of their capability to self-close and trap the analyte molecule in Raman hot spots. A possible approach to the manufacturing of such substrates consists of nano spheres lithography (NSL). It constitutes a low-cost and versatile alternative to traditional nanofabrication processes to obtain ordered structures with high uniformity over large area and high sensitivity (picomolar). It also grants great variability over geometrical features of the system of nanowires, such as diameter, length and inter-wire distance. The combination of NSL with two different etching processes, metal assisted chemical etching (MACE) and reactive ion etching (RIE), and the comparison between such methods allow to tailor the fabrication procedure to achieve fine control over the aspect ratio, crucial parameter for nanowires flexibility as well as SERS efficiency and reproducibility.

Resume : It is challenging to characterize Cu contamination in p-type Si via conventional lifetime methods as Cu ions are mainly in interstitial form, e.g. not recombination active. However, since interstitial Cu forms highly recombination-active defects under illumination, it has been proposed that lifetime measurement before and after illumination could be the way to measure Cu in Si. One of the main challenges in this approach is to separate Cu from other light-activated defects (e.g. Fe and B-O complex). Further challenges are expected in mc-Si, where spatial distribution of Cu is highly inhomogeneous due to segregation to extended defects, thus raising a need for high-resolution mapping. In this contribution, we study the possibility to use photoluminescence (PL) imaging to measure quantitative Cu concentrations in p-type Si. We show that indeed with PL imaging it is possible to obtain fast high-resolution (100 µm) spatial images of Cu distribution in mc-Si. Furthermore, we use newly determined recombination parameters for Cu light-induced degradation (LID) to single out Cu contamination from other defects, which could allow the determination of the Cu concentration. Therefore, in addition to proposing a new method for quantitative Cu imaging, PL imaging is a characterization tool that can be used to achieve further understanding of the mechanisms behind Cu-related LID, which is essential to prevent the harmful degradation effect.

Resume : Over the past few decades conventional Raman spectroscopy has seen a decrease in its attractiveness as a probe of composition and stress levels in semiconductor devices due to continuous and aggressive scaling. Recently however, nanofocused coupling of light into a periodic array of fins re-enabled the technique in deep-subwavelength structures, like for example high-mobility channels for finFET technology.[1,2] Specifically, for dimensions much smaller than the probing wavelength, the excitation light is confined into the region of interest, leading to an enhancement of the Raman scattering intensities over orders of magnitude. This transforms the response of very thin and narrow structures from hardly detectable to the dominant feature in the Raman spectrum. We demonstrate how the combination of this phenomenon with selective TO and LO phonon excitation enables quantitative metrology of stress at the nanoscale, without the need for additional sample preparation. Anisotropic biaxial stress is measured along and across sGe finFETs with channel widths down to 20 nm. The effect occurs in a variety of semiconductor materials, ultimately leading to a fast and versatile non-contact characterization of stress in industry-relevant channel materials and architectures. [1] Nuytten Appl. Phys. Lett. 106 033107 (2015) [2] Bogdanowicz Appl. Phys. Lett. 108 083106 (2016)

Resume : An accurate and non- destructive in-depth characterization of nanoscaled systems is an essential topic for today’s developments in many fields of research. The metrological challenges to sufficiently characterize such systems with respect to their in-depth elemental distributions require a further development of the current analytical techniques in parallel to the quickly increasing complexity of systems to be analyzed. A combined analysis using Grazing Incidence X-ray Fluorescence (GIXRF) and X-Ray Reflectometry (XRR) as proposed by de Boer [1] has already been shown to be capable of contributing to the in-depth analysis of nanoscaled materials. Here, the general approach to model the two experimental data sets using the density ρ, thickness d and roughness σ of each layer as the parameters can quickly result in numerous degrees of freedom and thus unreliable results [2]. In this work, XRR is combined with PTB’s reference-free GIXRF [3], providing a direct access to the mass depositions (ρd) of the present materials. This allows for a significant reduction of the degrees of freedom within the combined GIXRF-XRR modeling and thus improves the characterization reliability of the methodology. Employing the in-house built instrumentation [4] and radiometrically calibrated detectors at the laboratory of the PTB at the BESSY II synchrotron radiation facility, the reference-free GIXRF-XRR method is applied to the in-depth analysis of Al2O3-HfO2 nanolaminate stacks. References [1] D. de Boer et al., Spectrochim. Acta B 46(10), 1323 (1991). [2] P. Hönicke et al., Phys. Stat. Solidi A 212(3), 523 (2015). [3] M. Müller et al., Materials 7(4), 3147 (2014). [4] J. Lubeck et al., Rev. Sci. Instrum. 84, 045106 (2013).

Resume : In scanning-free grazing emission X-ray fluorescence (GEXRF) a range of discrete grazing emission angles is monitored at a fixed sample-detector geometry and using a position-sensitive detector [1]. This allows probing simultaneously depth ranges between a few nanometers below the surface up to several hundred nanometer, thus bridging the gap between probing techniques based on electrons and standard X-ray based techniques. The potential of this novel methodology in nanoelectronic, nanofabrication and quantum dot applications was demonstrated by characterizing the morphology of nanoparticles [2]. Furthermore the scanning-free GEXRF approach can be readily combined with X-ray absorption spectroscopy (XAS) in order to expand the element- and depth-sensitive character of GEXRF by the chemical sensitivity of fluorescence detected XAS [3]. Indeed, the knowledge on the depth dependence of chemical states allows for a better understanding of the physical and chemical properties at the surface and thus to contribute potentially to the investigation of dynamical processes. References [1] Y. Kayser, J. Szlachetko, and J. Sà, Rev. Sci. Instrum. 84 , 123102 (2013). [2] Y. Kayser, J. Sà, and J. Szlachetko, Nanoscale 7, 9320 (2015). [3] Y. Kayser, J. Sà, and J. Szlachetko, Anal. Chem. 87, 10815 (2015).

Resume : The main limitation in the analysis of thin films by means of grazing incidence X-ray reflectivity (GIXR) technique is that direct reconstruction of their optical constant profile from measured data is impossible because the phase of reflection is not known and the limited measurement range. The only way to analyze the GIXR data is to fit a calculated reflectivity curve to a measured one by varying parameters of a model of a thin film. In many cases the initial model does not take into account specifics of the analyzed samples, for example, the possibility of a density gradient inside a layer or formation of compound layers on the interfaces. In these cases accuracy of the GIXR data analysis will be limited by assumptions of the initial model what can be significantly less accurate than the actual accuracy defined by the data. We developed an assumption independent approach for the analysis of GIXR data from a thin film structure where the film is presented as a set of ultra-thin sublayers. Then we define a set of optical constants that are possible for a such sample and parameterize each optical constant with the digital array such that one number uniquely defines real and imaginary part of optical constant possible for such film. The minimization routine is used to fit the most optimal optical constant profile. In this approach a program is free to form any possible gradients and shapes of the interfaces using sets of physical possible material combinations.

Resume : An increasing field of application, e.g. in biotechnology is the dedicated adjustment of surface properties by functionalization with organic molecules. For a detailed understanding and further development of such nano-layers, a quantitative determination of the surface density of molecular species is required. By means of reference-free X-Ray Fluorescence (XRF) spectrometry such surfaces can be analyzed quantitatively by detecting specific marker elements. Using calibrated instrumentation and a quantification approach based on atomic fundamental parameters a SI-traceable quantitative analysis without any calibration sample or reference material is possible. A chemical analysis of molecular bonds can be accomplished by X-Ray Absorption Spectroscopy in the Near-Edge region (NEXAFS). Especially in the soft X-ray range an access to relevant light elements like Carbon C, Nitrogen N and Oxygen is possible. Here, aminated surfaces with varying densities of amino groups prepared from binary mixtures of silanes were investigated. In a complementary analysis by X-Ray Photoelectron Spectroscopy (XPS) and Fluorescence measurements based on laser-excitation in the optical light spectrum the functional-group density of silane monolayers were determined. The nitrogen atom in the head-group of the silane-molecule could be used as specific marker for the reference-free quantitative XRF analysis and were used for traceable calibration of XPS and Fluorescence Spectroscopy.

Resume : In industry organic coatings applied on substrates represent a valuable enhancement of the final product in several ways. Especially in the automotive industry they are typically employed to achieve decorative demands and fulfill a corrosion inhibitive purpose on top of the Zn-coated steel panels. Although these organic systems are widely used they are by far not fully understood. Segregation and migration effects of chemical groups inside the coating are responsible for, e.g., the adhesion performance and consequently the longevity of the final product. To investigate such systems X-ray photoelectron spectroscopy (XPS) is a powerful method that stands out due to its high surface sensitivity (< 10nm). Depth profiling in XPS is challenging, since ion sputtering leads to a prompt degradation of the chemical matrix [1]. Alternatively, the XPS analysis on conventional cross sections is not a choice either as the smallest spot size in XPS exceeds the coating thickness. In our work we suggest a different approach [2,3]. The sample sectioned with an ultra-low-angle microtome (ULAM). The exposed surface allows XPS measurements on top of the surface and in selected depths of the coating [3]. Furthermore, pull-off adhesion tests [4] were performed. Aside from probing the adhesion tensile strengths, the mixed mode failure patterns reveal sites of adhesive and cohesive failures to further perform XPS analysis. This procedure allows discussing the adhesion properties and the internal cohesiveness of the coatings on a nanometer scale. References: [1] A. Holländer, Plasma Process. Polym., 4, 773-776 (2007). [2] S.J. Hinder, J. Mater. Sci., 40, 285-293 (2005). [3] T. Greunz, Anal. Bioanal. Chem., 405, 7153-7160 (2013). [4] Pull-off test for adhesion, European Standard EN ISO 4624 : 2003. Acknowledgement: The author gratefully acknowledges the financial support by TWINFUSYON project.

Resume : X-ray photoelectron spectroscopy (XPS) is a powerful tool to investigate the surface chemical structure of any material. However, when applied to nanoobjects, this technique faces drawbacks due to interactions with a substrate, on which nanoobjects have to be deposited, and sample charging effects. We present a new experimental approach to XPS based on coupling soft x-ray synchrotron radiation with an in vacuum beam of free-standing nanoaerosols, focused by an aerodynamic lens system. Two examples of experiments performed on the PLEIADES beamline at the SOLEIL Synchrotron facility are presented to illustrate the effectiveness of this approach to probe the extreme surface of isolated nanoobjects. In the first example, the structure of the Si/SiO2 interface is probed on isolated silicon nanocrystals previously oxidized with ambient air or by heat treatment under air. Full characterization of the surface has been achieved for different sizes. In the second example, the adsorption of water on the surface of TiO2 nanoparticles is investigated in the gas phase. TiO2 free aerosols are exposed to a controlled pressure of water vapor before being analyzed on-line by XPS. The technique allows here the observation of a predominantly dissociative adsorption of water on the surface of TiO2 in its very first stage, highlighting a largely covered surface by OH groups.

Resume : Low Energy Ion Scattering (LEIS) is the most surface sensitive analytical technique available. While other surface analytical techniques probe a few atomic layers or even nm deep, LEIS determines the elemental composition of the outer surface. Since the outer surface governs the interaction of the material with the environment, LEIS data correlates directly with the macroscopic chemical and physical properties of the surface, e. g. catalytic activity, agglomeration, adhesion, etc. For a LEIS analysis, the sample is bombarded with keV noble gas ions. The mass of the scattering partner in the surface is deduced from the energy of the backscattered ions. Due to strong neutralization near the surface, ions scattered at the outer layer are detected with high intensity forming the so-called surface peaks; ions scattered in deeper layers are recorded with lower intensity and with an energy shift proportional to the depth. In this way, the composition of the surface and of the first few nm of the sample are determined separately. The extreme surface sensitivity together with the ability to analyse topographic and insulating material makes this technique extremely useful for a variety of real world samples. In this presentation LEIS is introduced, the experimental requirements are explained, and a number of examples from a range of nanomaterials will be demonstrated. This includes functionalised and core-shell nanoparticles, nanoparticles used for catalysis, and thin films.

Resume : Plasma Profiling Time Of Flight Mass Spectrometry (PP-TOFMS) is a chemical depth profiling technique combining a plasma source for sample sputtering and ionization with an orthogonal time of flight mass spectrometer. The main advantage is the short analysis time of about 5 minutes including sample introduction. In addition, low matrix effects and uniform sensitivity allow direct, standard-free, semi-quantitative analyses. A PP-TOFMS instrument (Horiba Scientific, Horiba Jobin Yvon SAS, France) has been recently installed in a clean room of the CEA-LETI in close proximity to process tools in order to provide fast feedback on materials development. In this paper we will first demonstrate the performances of the instrument on samples with mastered in-depth profiles such as epitaxial (SiGe/Si)*N multilayers and ultrathin multilayered structures grown by Ion Beam Deposition. We will then compare the elemental depth profiles deduced from PP-TOFMS with those obtained with well-established techniques through several examples in the area of energy and photonics. Several III-nitride materials used for power electronics are studied to evaluate dopant out-diffusion and elemental composition. Remarkable agreement was obtained with TOF-SIMS profiles even on innovative InAlGaN thin films. Moreover, In/Al ratios provided by PP-TOFMS using calibration-free ion beam ratios are aligned with Wavelength Dispersive X-Ray Fluorescence measurements.

Resume : Nanocarriers, in particular Lipid NanoParticles (LNP), represent a key support to improve drug delivery efficiency and are a promising tool for tumor chemotherapy (Peer et al., 2007; Mo et al.,2014; Kim et al., 2010; Muller et al., 2011; Bertrand and Leroux, 2012). LNP core is composed by a nanoemulsion of oil (liquid) and wax (solid) lipids, stabilized in aqueous medium by a PEGylated surface coating (Delmas, 2011). In this study, we focused on LNP manufactured by ultrasound or high pressure homogenization technologies (Delmas et al., 2011). Particle size distribution (PSD) and particle shape were characterized by Transmission Electron Microscopy (TEM). The PSD were compared to the results obtained by Dynamic Light Scattering (DLS) and Asymmetric Flow Field Fractionation (AF4). The particles were firstly observed by classical imaging (droplet drying) with and without negative staining and then by cryo-TEM. There is quite significant differences in the mean diameter measured by the different techniques. It may come from sample preparation methods. A way to picture the particle morphology in their close-to-application environment, avoiding complex sample preparation, is to observe LNP dispersion in-situ thanks to a liquid TEM holder. In order to enhance the contrast, the surface of the particles was functionalized with small gold nanoparticles. The pros and cons of the different microscopy methods will be further discussed in the presentation.

Resume : Finding the right metrology combination for a meaningful characterization of nanoscale biomedical objects is essential for the basic understanding of biological mechanisms in the human body. Here, we focus on the morphology, composition, and biomineralization of unusual objects in form of nanospherites found in osteoporotic human bone using multiple high resolution microscopy and spectroscopy techniques. SEM, BSEM, FIB, and TEM show the presence of nanospherites in many lacunae instead of normal osteocyte cells responsible for bone remodelling. Larger spherites formed by merging are also visible that can act as local plugs for the fluid flow through the lacuno-canalicular system affecting the communication between the bone cells. EDS and EELS reveal higher magnesium and calcium content within the nanospherites suggesting their cellular origins. Moreover, Raman and FTIR show that the lacunar occlusions have higher mineral-to-matrix and carbonate-to-phosphate ratios with respect to the surrounding bone matrix. All these differences point out that the regular bone matrix mineralization differs clearly from the mineralization mechanism based on the formation of nanospherites described herein. These results may guide future therapeutics toward maintaining osteocyte viability and fracture resistance of bone in elderly individuals. Our work demonstrates that even complex bio-nanomaterials can be accurately characterized by complementary analytical methods.

Resume : This work presents a unique and innovative combination of low voltage and energy filtered scanning electron microscopy (EF-SEM) which, via the detection and selection of specific secondary electron energies (SE Spectroscopy) allows for the mapping of molecular order on different length scales (nanometre to micrometres). Validation of this new technique is presented by observing a multi-phase semi-crystalline polypropylene (PP) film and comparing it to Raman hyperspectral imaging data. This heterogeneous semi-crystalline polymer which can be described as a three phase composite. Each phase is chemically identical but differs in conformation ranging from ordered crystalline (close-packed long chain helices), amorphous (randomly coiled helices or very short chains) and an intermediate phase termed mesophase (an ordered state within the amorphous region). The ratio of these phases will depend on the crystallization conditions, processing parameters and thermal history. As these membranes hold interest for use in many industrial applications including quantum dot templates and battery separators, significant interest lies in the correlation of its unique hierarchical architecture on the nanometre scale with its functionality on the micron scale. Further insights into how this advanced characterisation technique is elucidating on the morphology of PP and, indeed, other semicrystalline polymer systems e.g. silk will be presented.

Resume : Halide perovskites have great potential for many applications such as high-efficiency photovoltaic cells. The radiation-sensitive nature of halide perovskites has hindered structural studies at the atomic scale. We overcome this obstacle by applying low dose-rate in-line holography, which combines aberration-corrected high-resolution transmission electron microscopy with exit-wave reconstruction. This technique successfully yields the genuine atomic structure of ultrathin two-dimensional CsPbBr3 halide perovskites, and a quantitative structure determination was achieved atom column by atom column using the phase in-formation of the reconstructed exit-wave function without causing electron beam-induced sample alterations. An extraordinarily high image quality enables an unambiguous struc-tural analysis of coexisting high temperature and low temperature phases of CsPbBr3 in single particles. On a broader level, our approach offers unprecedented opportunities to better understand halide perovskites at the atomic level as well as other radiation-sensitive materials.

Resume : Ruthenium is one of the frequently used materials in the design of multilayers for EUV optics of different wavelengths, for example in Ru/B4C, Ru/B or Ru/C multilayers for 7-9 nm or Ru/Si as a specular broadband option for 12.5-14 nm, as well as a capping layer for various multilayers. Ruthenium forms very broad interfaces with Si, B4C, B and C. In this work the growth of magnetron sputtered Ru thin films on these materials was investigated by using in situ Low Energy Ion Scattering (LEIS). This technique has a unique sensitivity to the topmost atomic layer. Combination of in-vacuum transfer of samples and outermost surface sensitivity of LEIS allows us to quantify the surface composition for different thicknesses of Ru and therefore compose a “deposition depth profile”, which gives us knowledge of interface width, as well as the surface segregation effects and changes in surface density during compound formation. This method provides a much better depth sensitivity than traditional sputter depth profiles, and allows to resolve details that could not be seen before. After adding chemical interaction information from in-vacuum X-ray Photoelectron Spectroscopy (XPS), we propose growth mechanisms of Ru on these substrate materials. Among interesting effects found in this work is extremely strong surface segregation of C on Ru, persisting even after 30 nm of Ru deposited on a carbon substrate layer.

Resume : Interpreting the atomic structure of amorphous materials has attracted attention for a century and, in recent years, especially heterogeneous nanoglasses have fueled the interest because of their unusual structure and properties [1]. However, only few experimental means offer a way to characterize the disordered structures. Atomic radial distribution function (RDF) is one of the important tools, which was first applied for X-ray diffraction data of organic solids [2], and afterward extended to electron diffraction for inorganic glasses [3]. RDF describes the probability to find certain atomic pairs as a function of the pair separation and consequently, provides structural information in the short- and medium-range [3]. However, the traditional diffraction experiments only provide an average over large sample areas and lack spatial resolution especially at the nanometer scale. Critical information is hidden in the averaged signal. In this work, we demonstrate a newly developed scanning transmission electron microscopy (STEM) method, RDF-imaging [4], combining electron diffraction in STEM [5] with RDF and hyperspectral analysis to achieve structural mapping of multiphase amorphous materials with nanometer resolution. For this method, a 4-dimensional (D) diffraction map is acquired by recording diffraction patterns in STEM with quasi parallel nano-beam configuration and ~1 nm spot size. RDFs are calculated from all the diffraction patterns to construct a 3D data cube of RDFs. The data cube of RDFs can then be analyzed by hyperspectral analysis to obtain the phase map of the multiphase amorphous materials. The structures of each phase can be analyzed according to the corresponding RDFs in terms of bonding distance, bonding angle and coordination number. An application to amorphous ZrO2/ZrFe multilayers will be shown as an example. In addition to the unambiguously distinguished amorphous ZrO2 and ZrFe phases, an interface layer between ZrO2 and ZrFe was detected by RDF mapping, which could not be identified by traditional TEM techniques such as EELS and EDX maps. By analyzing the RDF, the atomic structure of the interfacial layers could be understood. It possesses the same atomic packing as that of the amorphous ZrO2 phase but with a 0.04 Ǻ shrinkage of the average bonding distance. The shift in the bonding distance could be due to O depletion and Fe incorporation. The detection of the interface layer shows the method is extremely sensitive to atomic packing variation. References [1] R Witte, T Feng, JX Fang, A Fischer, M Ghafari, R Kruk, R Brand, D Wang, H Hahn and H Gleiter, Appl Phys Lett 103 (2013), p. 073106. [2] T Egami and S J L Billinge in “Underneath the Bragg peaks structural analysis of complex materials”, (Elsevier Ltd, Kidlington, Oxford, UK), p. 55. [3] D J H Cockayne and D R Mckenzie, Acta Crystallographica Section A 44 (1988), p. 870. [4] X Mu, D Wang, T Feng, C Kübel, Ultramicroscopy 168 (2016), p. 1. [5] A Kobler, A Kashiwar, H Hahn, C Kübel, Ultramicroscopy 128 (2013), p.68.

Resume : X-ray Absorption spectroscopy, namely X-ray Absorption Near Edge Structure spectroscopy (XANES, EXAFS) and X-ray Emission Spectroscopy (XES), are well established methods for the chemical characterization of materials. Almost any synchrotron radiation facility offers beamlines and experimental stations for these methods. With this contribution, we present our achievements for XANES, EXAFS and XES spectroscopy with laboratory based instrumentation. Whereas the type of specimen, which can be investigated is limited in comparison to synchrotron radiation facilities, the permanent accessibility changes the way, how they can be used in material sciences. Laboratory instrumentation will render possible the use of XANES, EXAFS and XES for routine analysis of up to hundreds of samples per year. The presentation will give an overview of the setups we developed, their properties and possible improvements.

Resume : It is known that TXRF spectrometry is the most effective method for the surface material element analysis, today. In frame of the method the surface layer with thickness 3-5 nm is diagnosed and small level of the background deposit and absence of matrix effects are realized. Inasmuch as the exciting volume of the studied object is limited the radiation density of exciting beam is the critical parameter of TXRF measurements. Owing to this fact the planar X-ray waveguide-resonator (PXWR) is the best device for TXRF exciting beam formation [1]. At the same time, the waveguide-resonance conception allows to modify the waveguide-resonator design for the radiation density increasing in exciting volume. It can be achieved by PXWR application with nonequivalent lengths of its reflectors. The work discussed the radiation space distribution of X-ray fluxes formed by such PXWR and results of its application for TXRF. [1] V.K. Egorov, E.V. Egorov // Advances in X-ray Chem. Anal. Japan. v44. 2013. pp. 21-40.

Resume : The analysis of X-ray fluorescence and X-ray photoelectron spectroscopic methods requires in most cases the accurate knowledge of atomic fundamental parameters (FP) and optical constants involved. In addition, the lack of reference materials and calibration samples, in particular at the nanoscale, demands reliable reference-free quantification schemes in X-ray fluorescence analysis and related methods. As a consequence a higher accuracy of relevant FP is needed. However, the respective uncertainties of available tabulated data are usually relatively large, especially for low-Z elements or L- and M-shell fluorescence lines. In order to address this issue, different methods for experimental FP determinations have been developed and validated at PTB. The PTB operates two laboratories at synchrotron facilities in Berlin, Germany for metrological aspects. Hence, radiometrically calibrated instrumentation for photon detection is available over a broad spectral range from harder X-rays to visual and infrared radiation. This instrumentation is also used for advanced material characterization and facilitates in X-ray spectrometry the reference-free FP based quantization approach. The presentation will summarize relevant results and new methodologies employed in recent X-ray fundamental parameter determinations.

Resume : Organic components in photovoltaic (OPV) devices are comparably less stable against irradiation [M. JØrgensen et al. Adv. Mater. 24, 580; N. Grossiord et al., Org. Electr. 13, 432]. An extensive study of degradation processes, their mechanisms, and their dependence on radiant exposure and wavelength is, therefore, prerequisite for the fabrication of stable OPVs in the future. Such a study of degradation of organic thin films relevant for photovoltaic applications by the exposure of monochromatic and quantifiable synchrotron radiation in the spectral range from VUV to visible light is presented here. The irradiation procedure at the insertion device beamline at PTB’s own synchrotron radiation facility - the Metrology Light Source - is explained. The characterization of organic thin films and the investigation of ageing effects were carried out by in situ measurements of UV and X-ray photoelectron spectroscopy before and after radiant exposure [E. Darlatt et al. Nanotechnology 27, 324005]. The observed degradation effects are predominantly triggered by the energy of the incident photons. The radiant exposure during the monochromatic irradiation process plays a secondary role: pronounced effects were observed at the highest photon energy accompanied by a low radiant exposure. The funding through the European Metrology Research Program Project ENG53-ThinErgy is gratefully acknowledged. The EMRP is jointly funded by participating countries within EURAMET and the European Union.

Resume : As the 3D integration of circuits and devices is one of the key topics in today’s microelectronic industry, there is also an increasing demand for metrology in this field. In this contribution, reference-free X-ray spectrometry methodologies like grazing incidence X-Ray Fluorescence (XRF), X-ray reflectometry or µ-XRF are being applied to different metrological aspects from the field of 3D systems integration. One of the examples, where the X-ray fluorescence based techniques are potential contributors, is the non destructive and reliable defect analysis for high aspect ratio TSV (Through Silicon Via) interconnects in all steps of their fabrication. Another example is metal to metal wafer bonding, which is another key technique from this field, requires clean and oxide free metal surfaces. In this perspective, filled Cu TSVs interconnects with a Sn cap layer were probed by means of µ-XRF measurements in order to assess the presence of defects like voids in the interconnecting structures. Furthermore the presence of contaminants was verified at different processing steps of TSVs by means of reference-free XRF. In addition, we have studied the oxidation of clean metal surfaces by applying both reference-free XRF and X-ray absorption spectroscopy to different metal surfaces. Considering the non-destructive character of the X-ray spectrometric techniques, the presented experiments will demonstrate the potential to contribute eventually to the metrology for in-line process control measurements for the different 3D integration technologies.

Resume : In semiconductor research, as in many other advanced technologies, it is nowadays vital to reveal elemental distributions in all 3 dimensions with a high spatial resolution and sensitivity. To fulfill these needs, atom probe tomography (APT) has become an important driver in various material fields because it can reach a spatial resolution of better than 0.3 nm in all directions and a 50% detection efficiency. In this contribution, we will present the benefits along with the challenges of APT analysis for advanced semiconductor material research. Examples include the study of elemental diffusion in thin films for interconnect applications and III-V materials to 3D dopant profiling in nanostructures. Practical aspects are covered, including ion-beam based site specific sample preparation, the first obstacle to overcome for successful and reproducible APT analysis. Further on, we discuss the constraints on the counting statistics imposed by the limited analyzable volume, and the link between experimental conditions used and quantification accuracy. Finally, we allude to the root-causes behind the shape distortions observed within the reconstructed 3D image of complex structures comprising of numerous different materials.

Resume : The further development of more complex nano-materials and thin film applications with distinct properties needs an analysis independent from any reference material such as X-ray fluorescence analysis (XRF). A reliable quantitative XRF requires calibrated instrumentation. This work presents a high-resolution wavelength-dispersive spectrometer for XRF in the energy range of 2.3-19.0 keV. By using two full-cylindrical HAPG crystals as dispersive elements in modified von-Hamos geometry a large solid angle of detection and hence high efficiency is realized. This enables shortened measuring times while still having a compact design. Highly Annealed Pyrolytic Graphite (HAPG) is a synthetic type of carbon which forms mosaic crystals. Although the peak reflectivity is smaller than in perfect crystals, the diffraction profile of this mosaic crystal is much wider leading to an increased integrated reflectivity. A maximum peak reflectivity of more than 60 $\%$ was found for the used HAPG films of 40 $\mu m$ thickness on a cylindrical Zerodur substrate with a radius of 50 mm. The calibration of the spectrometer involves detailed characterization of the optics, a precise setup for determining a traceable energy axis, the efficiency and response function of the spectrometer as well as a detailed budget of respective uncertainties. Furthermore, comparison of the experimental results from the PTB-laboratory at the synchrotron facility BESSY II to a Monte-Carlo based ray-tracing simulation are presented allowing for discrimination of individual optical aberrations.

Resume : The Elettra XRF beamline [doi: 10.1117/12.2063009] is conceived as a multi-purpose beamline designed to accommodate a variety of end-stations dedicated to X-ray Spectrometry or Microscopy. Located at a bending magnet source, its monochromator is covering the photon energy range 3.6 - 14keV, with a resolving power of 1.4 10-4 (Si(111)). The excitation energy range is extended down to 700 eV by the use of multilayer coatings. The source is re-imaged to a 250 X 50 micron beam in an exit slit, with an angular divergence of 0.15 mrad and a transmitted flux of ~5 109 ph/s (5.5 keV, 2GeV). The XRF beamline is presently operating in collaboration with the IAEA an Ultra-High-Vacuum Chamber, based on a prototype [dx.doi.org/10.1063/1.4798299] designed and built by Physikalisch-Technische Bundesanstalt (PTB) and Technische Universitaet Berlin (TUB). This UHVC includes a motorized 7-axis goniometer allowing independent theta/2theta movements. The aim is to use tunable synchrotron X-rays with ~200 micron beamsize for various X-Ray Spectrometry techniques such as: Total Reflection X-ray fluorescence (XRF), Grazing Incidence/Exit XRF, X-Ray Reflectometry or X-ray Absorption Spectroscopy. A description of the beamline, analytical developments, and commissioning results will be presented. Highlights in the field of novel nanostructured layered materials will illustrate the interest of the combination and correlation of techniques that this setup offers to analyze nanoscale samples.

Resume : In order to evaluate the measurements of nanoscale objects using Grazing Incidence X-ray Fluorescence it is important to be able to characterise the X-ray distribution and related fluorescence signal generation in the analysed structures. This can be done analytically for simple and idealised objects, however for more realistic models we need to use numerical analysis, either based on geometrical optics or wave optics approach. We present a numerical approach for fast calculations of the X-ray Standing Wave field using graphics card based solver. The main benefit is that the solver is capable of handling and creating various complex geometries, including different sources of sample distortion and sample irregularities, like surface roughness or nano-object defects. Handling complex sample structures is especially important when analysing uncertainties of GIXRF measurements and one of the goals of the presented algorithm is therefore to be able to perform simulations fast enough to be able to perform uncertainty analysis - e.g. using Monte Carlo uncertainty propagation technique. We will show comparisons between calculations and experimental GIXRF data taken on artificial nano structured samples, e.g. semi-spherical Ag dots or electron beam lithography produces Cr blocks and cylinders.

Resume : We present an experimental system to combine surface plasmon resonance and X-ray absorption spectroscopy: SPR-XAS setup [1,2]. The system allows the study of the interaction between electromagnetic radiation and matter using one type of radiation to modify the material and the other one as a probe, performing the study in real time and in situ. The surface plasmons, measured under the Kretschmann-Raether configuration [3], can be used to monitor in situ changes induced by the X-rays in the metallic film, the substrate and the top dielectric medium [4,5]. Similarly, the changes in the electronic configuration of the material when surface plasmons are excited can be measured by X-ray absorption spectroscopy [1]. The resolution of the system allows observing changes in the signals of the order of 10-3 to 10-5 depending on the particular experiment and used configuration. The device has been mounted at the SpLine BM25 beamline at ESRF in Grenoble, France, and it is currently available for experiments. References [1] A. Serrano, O. Rodríguez de la Fuente, V. Collado, J. Rubio-Zuazo, C. Monton , G. R. Castro and M. A. Garcia, Rev. Sci. Instrum., 83 (2012) 093102. [2] A. Serrano, Modified Au-Based Nanomaterials Studied by Surface Plasmon Resonance Spectroscopy, Springer Theses (2015). [3] H. Raether Surface Plasmons on Smooth and Rough Surfaces and on Gratings, (1988) Berlin: Springer. [4] A. Serrano A, F. Gálvez, O. Rodríguez de la Fuente and M.A. Garcia, J. Appl. Phys. 113 (2013) 113104. [5] A. Serrano, O. Rodríguez de la Fuente, C. Monton, A. Muñoz-Noval, I. Valmianski, J. F. Fernández, G. R. Castro, Ivan K. Schuller and M. A. García, J. Phys. D: Appl. Phys., 49 (2016) 125503.

Resume : CASTOR is a new instrument dedicated to the characterization of thin films with thicknesses in the nanometer range now operated at SOLEIL synchrotron facility on the METROLOGIE beamline. The instrument combines X-ray reflectivity (XRR) with X-ray fluorescence (XRF) measurements and especially allow for total reflection X-ray fluorescence-related techniques such as grazing incidence XRF (GIXRF). The instrument can be operated on the two branches of the beamline making possible experiments over a wide range of photon energies (45 eV to 40 keV). A heating sample holder was developed to allow the sample temperature to be controlled up to 300°C. The CASTOR goniometer is designed upon a model developed at Physikalisch-Technische Bundesanstalt (PTB). Some examples of the first application of CASTOR will be presented, ranging from combined GIXRF-XRR analysis on series of high-k materials prepared by CEA-LETI, which are of great interest for the semiconductor industry, to telluride-based material (identical and comparative experiment conducted at SOLEIL and ELETTRA), important for advanced resistive memories and photovoltaics applications, to planar X-ray waveguides with ZrC/Al core. The performance of the heating sample holder will be illustrated by in-situ XRR measurements of thin films (GeTe and Ge2Sb2Te5) in order to observe the phase transition of the materials. Finally, the current limitation and foreseen developments and optimizations will be discussed.

Resume : Characterization of the structure of the crystal surface is essential for next generation electronics devices. Such as spin injection structures and topological insulators, to name a few. We have studied the advantages of characterization of the crystal surface based on the analysis of modulations of specular X-ray reflection occurred during the azimuthal scan in grazing incidence X-ray diffraction (GID) geometry. In GID geometry incidence angle is fixed, therefore specularly reflected beam typically does not change during the azimuthal rotation of the sample. Unless, sample is aligned to a Bragg diffraction conditions where a modulation of specularly reflected beam intensity occurs. This modulation is known to be sensitive to thickness of the surface (amorphous layer or distorted crystal layer) on an angstrom level [Bushuev, V. A., et al Journal of Physics D: Applied Physics 35.12 (2002): 1422]. Mathematical simulation showed that the thickness of the surface layer affects modulation of specular reflectivity in GID even without optical contrast between the surface and the bulk of material. In addition, simulation showed that in that technique density and thickness of the surface layer are not correlated. We expect that simple geometry and high brightness of the specularly reflected beam will allow to implement that technique on the lab diffractometer, on the contrary to the crystal truncation rod, that only can be implemented at synchrotron.

Resume : As an analytical surface method the Auger electron spectroscopy (AES) for the Micro and Nano range is on the same level as other methods as TEM, XPS, APT, TOF-SIMS and HR-REM. AES is used to determine the elemental composition and, in many cases, the chemical state of the atoms in the surface region of a solid, vacuum stable, not insulating material. AES has found widespread use in an extensive variety of material applications, especially those requiring surface specificity and high spatial resolution. The method is based on the Auger effect which is resulting from inter- and intrastate transitions of electrons in an excited atom. Due to the relatively low kinetic energy of Auger electrons they can only escape from the uppermost few monolayers of a specimen surface. This is the reason for the high surface sensitivity of this technique. In combination with Ar ion sputtering depth profiles to 1000 nm are available without prior sample preparation. In many cases there is no complex and time-consuming sample preparation needed. We will show depth profiling of a multilayer to control the diffusion behavior with a resolution less than 1 nm, elemental mapping of laser structured material and quantitative phase analysis. Furthermore, we are able to break samples in ultra high vacuum to look for the elemental distribution at the grain boundaries and inside the crystals.

Resume : Inline characterization of nanoparticle formation with particle mass spectrometry (PMS) is well established to investigate the evolution of particle size and particle size distribution during low pressure nanoparticle synthesis. It is commonly used to determine the influence of process conditions on particle growth. The method is based on a molecular beam sampling and is equipped with a deflection unit and an off-axis Faraday cup detector to measure deflected, energy-filtered currents of size-selected charged particles. Conventional PMS systems are limited to low-pressure sampling (< 100 mbar). In this study, we present a newly developed PMS that can be operated at atmospheric pressure. It consists of a two nozzle/skimmer system integrating an additional pre-expansion chamber to connect the PMS to reactors working at atmospheric pressure. This chamber allows sampling and dilution of particles thus preserving the particles’ properties by adding inert gases. With a delay of a few microseconds, the aerosol is sampled via the commonly used PMS extraction system. The additional pre-expansion chamber enables operation of the PMS within a wide pressure range between 5 mbar and atmospheric pressure. The nanoparticle sampling rate can be tuned by diluting, and adjusting the pressure in the pre-expansion chamber. The setup allows for spatially-resolved investigations of particle formation. Results from spray-flame synthesis of metal oxides at ambient pressure will be discussed.

Resume : The determination of fundamental parameters (FP) is an important part of the reliable, reference free quantitative X-ray fluorescence analysis (XRF) [1,2]. In order to reduce the uncertainties of the FP, transmission measurements of the samples and self-absorption correction has to be experimentally determined. For reference free quantitative XRF, the uncertainty of the fluorescence yield is crucial for the total uncertainty of the quantification. In this work, the fluorescence yield of Ga L3 was determined with low uncertainties in order to have a reliable quantification of Ga in an advanced PV application material (TCO). Due to the high absorption of radiation in the soft x-ray range, it is necessary to reduce the thickness of the samples for the transmission measurements. Here, a nominal 300 nm thin GaSe layer was deposited on a silicon-nitrate window to be able to measure the transmission. The measurements were carried out at the plane-grating monochromator (PGM) beamline in the PTB laboratory at BESSY II using monochromatized undulator radiation and calibrated instrumentation [3,4]. [1] P. Hönicke et al., Spectrochim. Acta B (2016) 124, 94-98 [2] P. Hönicke et al., X-ray spectrometry (2016) 45(4), 207-211 [3] B. Beckhoff et al., Anal. Chem. 79, (2007), 7873 [4] B. Beckhoff, J. Anal. At. Spectrom. 23, (2008), 845

Resume : Gram-negative bacteria innately possess resistance to antibiotics as a consequence of the combinatorial effects of two permeability barriers: the outer and inner bacterial cell membranes, their ability to efflux antibiotics out of the cell and their capacity to form antibiotic tolerant biofilms that are up to 100 times more resistant than planktonic bacterial cells. The objectives of the EMPIR project Metrology vs. Bad Bugs is to provide the urgently needed essential metrology to quantitatively measure and image the localization of antibiotics/biocides and to understand the penetration and efflux processes in bacteria and biofilms. In this contribution, an overview of the ongoing reference-free (soft) X-ray spectrometry studies (grazing incidence X-Ray fluorescence (GIXRF), micro-X-ray fluorescence (µ-XRF), near edge X-ray absorption fine structure (NEXAFS), near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS)) on the penetration of biocides/antibiotics into bacteria and biofilms is given. A specifically adapted liquid cell is utilized and allows for in-situ traceable quantification of the vertical concentration profiles of antibiotics in bacteria- and biofilms. The liquid cell can be applied for X-ray and IR analysis alike and will feature an option for UHV compatibility. Complementary techniques for XRF depth profiling involve line intensity ratio modifications and grazing incidence variations. These studies will have an impact on the wide range of biological and biomedical research as it will enable studies of biological samples by XRF methods, which has not been possible thus far, due to the high-vacuum requirements of these techniques.

Resume : Small-Angle X-ray Scattering (SAXS) is a powerful technique to study particle structure, size and size distribution on statistical relevant particle ensembles. Synchrotron based instruments provide a time resolution of seconds, sufficient for in situ investigation of nanoparticle synthesis if an appropriate sample environment is available. Therefore a sample environment for liquid samples will be presented that is elegant designed to enable SAXS, as well as WAXS and X-ray absorption and fluorescence spectroscopy in air and also under vacuum. It is suitable for acids, bases and the most organic solvents and withstands pressures up to 40 bar. Thereby this environment provides a weak scattering background with scattering intensities similar to the incoherent scattering of solvents and a good transmissivity above 4 keV photon energy. This environment was already used at Synchrotron sources Elettra [1] and ESRF [2] in an in situ SAXS/WAXS set up combined with a UV/Vis spectrometer to investigate the microwave-assisted solvothermal synthesis (MWASS) of magnetic nanomarticles (particle growth in 5 to 10 min, ripening in 10 to 30 min). MWASS allows a precise control of pressure and temperature inside a sealed reaction vessel for the preparation of monodisperse and crystalline metal and metal oxide nanoparticles. [3,4] Some results from these experiments will be presented allowing unique insights in the particles growth mechanisms, the growth kinetics and thermodynamics during a MWASS. [1] H. Amenitsch, S. Bernstorff and P. Laggner, Rev. Sci. Instrum. 1995, 66, 1624 [2] M. Borsboom, W. Bras, I. Cerjak, D. Detollenaere, D. Glastra van Loon, P. Goedtkindt, M. Konijnenburg, P. Lassing, Y. K. Levine, B. Munneke, M. Oversluizen, R. van Tolb, and E. Vliega, J. Synchrotron Rad. 1998, 5, 518. [3] I-M. Grabs, C. Brandtmöller, D. Menzel, G. Garnweitner, Cryst. Growth Des. 2012, 12, 1469. [4] I. Bilecka, P. Elser, M. Niederberger, ACS Nano 2009, 3, 467.

Resume : There is a strong need in medical device industry to decrease failure rates of biomedical devices by the reduction of defect structures and contaminants during the production process. As reliable detection and identification of defect structures and contaminants is a crucial aspect for industrial applications. The present study aims to provide an analytical tool for the reliable and traceable characterization of surface contaminants of medical devices, in particular N,N’-ethylene-bis (stearamide). Reference-free X-ray fluorescence analysis as primary method has proven to being able to lay foundation for all other applied methods since it yields the absolute mass deposition of the selected contaminant whilst X-ray absorption fine structure analysis confirms the chemical species of this compound. Ambient vibrational spectroscopic methodologies such as FTIR and Raman spectrometry are involved in this systematic procedure for an extensive complementary analysis. This analysis procedure was developed using model systems varying in thickness and substrate material. Furthermore, typical real medical devices such as both a polyethylene hipliner and a silver-coated wound dressing have been dedicatedly contaminated and investigated by these diverse methods, enabling validation of this developed procedure for both devices. These findings clearly demonstrate the potential of combining orthogonal methods for a better understanding of the relevant complex organic layered structures.

Resume : The continuous and aggressive scaling in semiconductor technology results in the integration of increasingly complex, 3D architectures and new materials. The realization of these down-scaled 3D structures implies further improvement in 3D chemical characterization techniques. In this work, a potential route to improve accuracy and reliability in quantitative analysis of 3D nano-devices is being developed. Therefore, we work on the fabrication of suitable reference nanostructures that resemble state-of-the-art devices in view of material composition, dimensions or their 3D architecture. These 3D nanostructures were fabricated using Di-Block Copolymer (DBC) lithography [1] or electron beam lithography (EBL), and various coatings of (in)organic materials were deposited. The nanostructures are being quantified for the amount of material present within defined dimensions using reference-free grazing incidence X-Ray fluorescence analysis (GIXRF) [2]. Eventually, these well-characterized, reference structures might provide a future platform to calibrate other characterization techniques such as atom probe tomography (APT). This technique is of great relevance for the determination of the 3D elemental distribution in 3D nano-devices with near-atomic resolution, but it currently lacks standardization and hence results may be inaccurate and unreliable. 1. F. Ferrarese Lupi et al., ACS applied materials & interfaces 6.10 (2014): 7180-7188 2. P. Hönicke et al., Journal of Analytical Atomic Spectrometry 27.9 (2012): 1432-1438

Resume : The performance of heterogeneous 3D transistors depends on the composition and strain state of the buffer, channel and source/drain regions. In this paper we use in-line high resolution X-ray diffraction (HRXRD) to study the composition and strain of various (Si)Ge fin structures down to 16nm in width. We fabricated fins of identical dimensions into arrays which we analyzed using an in-line HRXRD tool from Bruker equipped with a micro-beam X-ray source and an automated pattern recognition system. To analyze the fins’ composition and strain state as well as modifications to these parameters during fabrication, we collected ω-2Θ scans using a conventional (0D) scintillation detector and reciprocal space maps (RSMs) using a linear (1D) detector. We will discuss the relevance of such measurements using three representative examples: First we will analyze the composition and strain of relaxed SiGe fins grown in an STI matrix where we found an anisotropic in-plane relaxation with significantly reduced relaxation in the direction along the fin as the fin width is reduced. Secondly, we will analyze the strain state of etched Ge fins in the two in-plane directions and show that ω-2Θ scans can provide quick feedback on (undesired) relaxation occurring during fabrication. Finally, we will demonstrate the value of HRXRD for the analysis of multilayer fins which are relevant for horizontal nanowire FETs that are candidates to replace FinFETs below the 7 nm node.

Resume : Solvothermal syntheses are one of most applied methods in the preparation of crystalline and monodisperse metal oxide nanoparticles.[1,2] Nevertheless the drawbacks of this method are long reaction times, expansive autoclaves and the impossibility of investigations of nanoparticle growth. In consequence of these, microwave-assisted solvothermal syntheses (MWASS) have become subject of renewed fundamental and applied interests.[3] Main features of MWASS are distinguished control and exact on-line determination of pressure and temperature inside the sealed vessel that can be understood as an autoclave-type reactor. The advantage in contrast to conventional heating is the efficient internal volumetric “in-core” heating by direct coupling of MW energy to the reaction molecules. It allows high heating rates with small thermal gradients and strongly decreased reaction times based on the Arrhenius law.[4] This work includes innovative in-situ investigations of the formation and growth mechanisms of iron oxide nanoparticles by this newly developed MWASS-system. It allows exact additions of precursor solution into the sealed vessel reactor and withdrawals of colloid solution at any time. Thereby, we are able to investigate and characterize the nanoparticles in a time-range of seconds by in-situ UV-Vis spectroscopy and synchrotron small-angle X-ray scattering and ex situ by TEM, EELS and EXAFS. With the help of these results, we provide concepts for the formation and growth mechanism. [1] I-M. Grabs, C. Brandtmöller, D. Menzel, G. Garnweitner, Cryst. Growth Des. 2012, 12, 1469-1475. [2] N. Pinna, G. Neri, M. Antonietti, M. Niederberger, Angew. Chem. Int. Ed. 2004, 43, 4345-4349. [3] I. Bilecka, P. Elser, M. Niederberger, ACS Nano 2009, 3, 467-477. [4] M. Baghbanzadeh, L. Carbone, P.D. Cozzoli, C.O. Kappe, Angew. Chem. Int. Ed. 2011, 50, 11312-11359.

Resume : Several applications of ex-situ and in-situ Spectroscopic Mueller Matrix Ellipsometry (SMME) for the study of self-assembled nanostructured surfaces and highly ordered plasmonic metasurfaces are covered. Applications ranges from anti-reflection coatings, PV-absorbers, nanoimprinting masks, plasmonic polarizers, plasmonic meta-materials, hyperbolic metamaterials and meta-surfaces. The optical analysis is in all examples systematically accompanied by AFM, SEM and TEM. SMME with variable angle of incidence and full azimuthal rotation of the sample is shown to be a powerful optical technique to characterize both anisotropic and bi-anisotropic materials. It is demonstrated how the generalized Bruggeman effective medium theory efficiently extracts structural information from self assembled systems, such as self-assembled straight and tilted GaSb nanopillars [Le Roy et al., Phys. Rev. B 2010, Nerbo et al. Appl. Phys. Lett. 2009]. Similarly, the effective medium theory for superlattices is exploited to extract the hyperbolic optical properties of self-assembled hyperbolic meta-materials [X. Wang et al. JOLT (2017)]. The second part of the presentation discusses the fascinating Mueller matrix response of highly organized arrays of Au nanoparticles on glass, produced by Focused-Ion-Beam milling. The response is discussed in the context of highly organized meta-surfaces and plasmonic photonic crystals [Brakstad et al. Opt. Express 2015]. In particular we point out the existence of strong polarization coupling, the influence of the Rayleigh lines in addition to the localization of the plasmon resonance. We show that such a complex Mueller matrix response can be highly efficiently modeled both exploring the Rayleigh lines, and through the use of more advanced computational Electromagnetics modeling, and thus used in both monitoring and control of the manufacture of such surfaces.

Resume : As the applications of nanotechnology become widespread, three-dimensional shape analysis of micro/nanostructures with sub-nanometer scale measurement resolution becomes important. At present, a universally applicable measurement tool does not exist, and in general, there are tradeoffs among performance characteristics of widely used tools. For example, scanning electron microscopy (SEM) readily provides excellent lateral imaging resolution but vertical measurement is challenging. In addition, it also requires vacuum, unacceptable for certain applications. Critical-dimension atomic force microscopy (CD-AFM), in contrast, exhibits excellent three-axis resolution in air, but is much slower and is limited in density of structures that can be imaged. However, an economical, versatile and high-throughput tool that provides 3D nanoscale measurement with least number of negatives is highly desirable, especially for industrial nanomanufacturing. In conventional optical microscopy, out-of-focus images are ordinarily considered not particularly useful, especially for metrology applications. This is based on the generally accepted assumption that optical information from out of focus planes is either less useful or detrimental compared to information from the best focus plane. However, a complete set of out-of-focus images contains more additional information about the target as compared to a single best-focus image. This additional information can be extracted by "through-focus scanning optical microscopy" (TSOM). A typical TSOM image is a cross-section constructed from the four-dimensional (4-D) optical data acquired using a conventional optical microscope as a target is scanned along the focus direction. TSOM shows considerable promise in meeting the industrial requirement of high throughput and low-cost 3D shape metrology. TSOM transforms a conventional and ubiquitous optical microscope into a powerful 3D shape metrology tool and provides nanoscale measurement resolution comparable to SEM and AFM in both lateral and vertical directions. One of the unique characteristics of the TSOM method is its ability to reduce or eliminate optical cross correlations, often challenging for optical based metrology tools. TSOM usually has the ability to separate different dimensional differences (i.e., the ability to distinguish, for example, linewidth difference from line height difference) and hence it is expected to reduce measurement uncertainty. We present several examples showing the versatility of the TSOM for target dimensions ranging from one nm to over 100 m (over five orders or magnitude size range). As an example, we present experimental size and 3D shape analysis of nominally 45 nm to 55 nm wide isolated Si on Si lines with near sub-nanometer measurement resolution using 546 nm wavelength, which is beyond the classical Raleigh image resolution limit. Dimensional analysis of islands as small as 500 nm diameter and one-nanometer thickness will also be presented using TSOM. TSOM is applicable to a wide variety of target materials ranging from transparent to opaque, and shapes ranging from simple nanoparticles to complex semiconductor memory structures, including buried structures under transparent films. Demonstrated applications of TSOM include critical dimension (linewidth), overlay, patterned defect detection and analysis, FinFETs, nanoparticles, photo-mask linewidth, thin-film thickness, through-silicon vias (TSVs), high-aspect-ratio (HAR) targets and others with several potential three-dimensional shape process monitoring applications such as MEMS/NEMS devices, micro/nanofluidic channels, flexible electronics, self-assembled nanostructures, and waveguides. Numerous industries could benefit from the TSOM method —such as the semiconductor industry, MEMS, NEMS, biotechnology, nanomanufacturing, nanometrology, data storage, and photonics.

Resume : The porosity of surface coatings determines their performance and applicability in many applications in the fields of catalytic chemistry, electrochemistry, electronics and photovoltaics. Therefore, a fast and non-destructive method of determining the porosity of coatings is most desirable. In this work, we apply ellipsometric porosity to measuring the void fraction present in proe-controlled sol-gel synthesised TiO2 layers on Silicon. The goniospectral ellipsometric data were collected on a range of samples with different TiO2 layer thickness and different porosity values. The type of samples used here are produced by templated coating and exhibit a well-defined pore size and pore density. The ellipsometry measurement data were analysed by means of a Bruggeman effective medium approximation (BEMA), with the aim to determine the mixture ratio of void and matrix material by a multi-sample analysis strategy. This analysis yielded porosities and layer thicknesses for all samples as well as the dielectric function for the matrix material. Following the idea of multi-method techniques in metrology, the data was referenced to imaging by electron microscopy (SEM) and to a new EPMA (electron probe microanalysis) porosity approach for thin film analysis. This work might lead to a better metrological understanding of optical porosimetry in its various forms and to traceable optical characterisation methods for nano-porous layer systems.

Resume : In this contribution, we demonstrate a combination of phase imaging scanning microscopy and spectroscopic ellipsometry as a non destructive way to detect the coexistence of buried unexpected crystallographic phases in liquid-shell/solid-core nanoparticles supported on a variety of substrates, and simultaneous detect their optical plasmonic response. In this way, we are able to establish a direct correlation between the complex multi-phase structure of a nanoparticle and its plasmonic response. The data are interpreted and validated by a combination of high-resolution of cross-sectional transmission electron microscopy (TEM), high resolution HAADF-STEM (high angle annular dark field scanning transmission electron microscopy) imaging, SAED (selected-area electron diffraction), chemical composition analysis by STEM-EDS (energy dispersive spectroscopy). This multi-technique is applied to plasmonic core-shell nanoparticles of Ga, Ga/Au and Ga/Ag that exhibit a large degree of polymorphism that enable new devices based on phase changes, such as optical switches and memories and active plasmonic platforms. Our multi-techniques provides a general framework for understanding how nanoconfinement, energy considerations and interaction with surfaces can impact surface-assisted phase transitions and enable and stabilize coexistence of phases otherwise unexpected for bulk materials. Most broadly, we also reveal that phase engineering can be engineered and controlled by the stiffness/deformability of the support of nanosystems. We acknowledge the contribution of the H2020 European programme under the project TWINFUSYON (GA692034).

Resume : Nanoscaled materials, now widely used in many different modern technologies, are a challenge for characterization. Instruments capable of measuring large areas with nanometer resolution in three dimensions are few. Optical label-free nanoscopy techniques present several hopeful candidates for 3D nanocharacterization. The resolving power of optical microscopy was for a long time limited by the diffraction of light to a value of approximately half the wavelength of the light used. In the visible range, the smallest lateral distance between two resolved objects is 200 nm in air. Several methods have been developed to overcome this limitation, amongst them microsphere-assisted microscopy. This far-field and full-field imaging technique provides high resolution using a transparent microsphere placed on the sample. Here, we present an enhancement of optical profilometry using microsphere-assisted phase-shifting nanoscopy and a Linnik architecture. A microsphere is placed on the nano-structures and illuminated by a white-light LED beam. We demonstrate an improvement of a factor of 4.7 in the lateral resolution, well beyond the diffraction limit, while combining this with the nanometric axial resolution of interferometry. Results are shown of the characterization of periodical Ag nano-dots covered by a SiON layer obtained by nano imprint lithography, and of periodic ripples, spaced by a few hundred nanometers, made by a femtosecond pulsed laser technique on stainless steel.

Resume : X-ray based techniques such as X-ray Absorption or Emission spectroscopies have been known for several decades to be instrumental in determining the local and electronic structure of non-crystalline materials. These techniques have been most often applied to materials under ex situ conditions, before and/or after being exposed to external stresses. The high brilliance available at modern, third generation synchrotrons now allows applying X-ray techniques to materials while they are being modified by a physical (such as pressure or an electric field) or chemical (such as a solvent or a gas) processes. These measurements under in situ conditions are particularly important to understand the mechanism by which the structure of materials is modified under an external constraint. Operando setups can also be designed to follow the modifications within a material during a chemical reaction. This presentation will give a brief overview of the information that can be obtained on (nano)materials using X-ray spectroscopies. The study of energy-related electrocatalytic reactions will be used as examples to show how X-ray spectroscopy can be used to understand the structure of a material under reacting conditions and eventually describe a reaction mechanism. We will present two systems that use operando setups in the hard and tender X-ray energy ranges. The first system describes the electrodespotion of cobalt nanoparticles from a molecular precursor and the subsequent use of these nanoparticles as catalysts for the Hydrogen Evolving Reaction (HER). Using operando X-ray absorption spectroscopy, we show that the material maintains a layer that is not purely metallic at the solid-liquid interface. The second system describes an electrodeposited molybdenum sulfide amorphous material, which is also active for the HER. We propose a model, using a combination of operando hard and tender X-ray absorption spectroscopies, in which the active species involved in the catalytic mechanism is a Mo(III) ion with terminal disulfide units. These results show how operando XAS can be instrumental in unravelling a reaction mechanism and, more generally, in characterizing materials under functioning conditions.

Resume : Organic molecules gain importance for a variety of different fields of application and therefore the necessity for a reliable and traceable analysis is increased, too. But, there is also a lack of reference material or calibration specimens in this field. Here, our work focuses on the development of reference procedures by using complementary methods. By means of a system consisting of adsorbed fibrinogen layers on gold and glassy carbon the procedure was validated and the material properties were investigated. In particular, the capabilities of plasmon-enhanced, multiple-angle of incidence spectroscopic ellipsometry (SE [1]), Grazing Incidence X-Ray fluorescence (GIXRF [2]) analysis as well as Near-Edge X-ray absorption fine structure (NEXAFS) spectroscopy were evaluated for organic materials. In case of SE, the sensitivity was studied in terms of measurement and layer system configurations – in particular for the gold layer thickness. From these measurements, the homogeneity and optical properties of the protein layers were obtained, as well as the amount of adsorbed protein [3] and the chemical binding states. The X-ray methods were employed to quantify the absolute amount of adsorbed molecules including information about the chemical species, and to verify the SE results. Combining both methods, the results of the quantitative GIXRF analysis particularly supports the modeling of the data gained by SE. Independent information of thickness and elemental composition may reduce the number of needed parameters and ensures more reliable results on SE. References [1] J. Nador, B. Kalas, A. Saftics, E. Agocs, P. Kozma, L. Korosi, I. Szekacs, M. Fried, R. Horvath, P. Petrik, Optics Express 24 (2016) 4812. [2] B. Beckhoff, R. Fliegauf, M. Kolbe, M. Müller, J. Weser, and G. Ulm, Anal. Chem., 79, (2007) 7873. [3] J. A. De Feijter, J. Benjamin, and F. A. Veer, " Ellipsometry as a tool to study the adsorption behavior of synthetic and biopolymers at the airwater interface. " Unilever Research, (1977) page 1759

Resume : For high-resolution X-ray Emission Spectroscopy (XES), crystal-based Wavelength-Dispersive Spectrometers (WDS) can be applied for effective speciation characterization of nano- and microscaled materials. A von Hamos geometry provides among the highest detection efficiencies combined with high resolving power. This geometry uses a cylindrically bent crystal as dispersive and as a sagittal focusing optic. Highly Annealed Pyrolytic Graphite (HAPG) [1] can be deposited reliably on cylindrical glass substrates and shows highly integrated reflectivity while offering low mosaicity, ensuring high resolving power [2]. A novel calibratable von Hamos X-ray spectrometer based on two full-cylinder optics is being put into operation at the PTB. The spectrometer enables chemical speciation of elements in an energy range from above 10 keV down to 2.3 keV. The first results using synchrotron radiation as the excitation source will be presented. The spectrometer combines high efficiency with high spectral resolution in a compact arrangement also suitable for laboratory arrangements References [1] H. Legall, H. Stiel, A. Antonov, I. Grigorieva, V. Arkadiev, A. A. Bjeoumikhov, and A. Erko (2006). Proc. FEL, BESSY FRAAU04, 798 – 801 [2] M. Gerlach, l. Anklamm, A. Antonov, I. Grigorieva, I. Holfelder, B. Kanngießer, H. Legall, W. Malzer, C.Schlesiger, B. Beckhoff (2015). J. Appl. Cryst. 48, 2015, 1381-1390

Resume : In the last years the block copolymers (BCPs) have emerged as interesting materials useful for the realisation of new 3D nano-structured metrology reference standards based on invariants of nature. In this context the perfect control over the BCP orientation and ordering is a mandatory step. In this work in-depth Grazing Incidence Small Angle X-ray Scattering (GISAXS) has been performed in order to monitor the evolution of the morphology of cylinder forming PS-b-PMMA BCPs thick films annealed at high temperatures. With this non-distructive technique we observed the formation of buried layers composed of both parallel and perpendicular oriented cylinders as a function of the film thickness h (in the range between 24 and 840 nm) and annealing time (from 0 to 900 s). In particular, we have been able to identify three distinct behaviors as a function of the film thickness. Up to h ≤ 160 nm we observed the presence of a homogeneous film consisting of perpendicularly oriented cylinders, while for h comprised between 160 and 700 nm a decoupling process between both the air-BCP and the substrate BCP interfaces takes place. Finally for h > 700 nm, the two interfaces are completely decoupled and the formation of a superficial layer of about 50 nm composed of perpendicular cylinders was observed. This work has been carried out in the framework of the project 14IND01 “3DMetChemIT”, founded by the EMPIR programme, co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.

Resume : For the characterization of the profile used in diffraction gratings one usually refers to scans being made by use of scanning electron or atomic force microscopes. These techniques cover only very small areas, which make difficult to extrapolate the grating performance in terms of expected diffraction efficiency. When subjecting a sample to X-ray grazing incidence conditions, the investigated area at the grating is significantly increased. By combining angularly resolved Grazing Incidence X-ray fluorescence spectroscopy (GIXRF) and X-ray reflectivity (XRR), one has then access to the sample’s depth composition, given by the angularly resolved fluorescence contributions of the materials’ elements and to its optical parameters, respectively. This study wants to illustrate the performance of GIXRF in the characterization of such periodic structures. A grating with laminar profile has been measured systematically depending on the grazing angle of incidence and on the orientation angle of the structure around its pole. When the trajectory of the probing beam is parallel to grooves with flat side walls, one should not be able to distinguish between the XRR and GIXRF from these periodic structures and from those from unruled areas on the same substrate. Any discrepancy would thus point onto defects in the profile. When in the orthogonal orientation, the GIXRF from buried layers should exhibit significantly different behavior, depending on their groove spacing and groove profile.

Resume : Radiation has been for a long time and continues to be the primary probe for looking into "matter". I will showcase a serious of experiments where x-rays and neutrons from accelerator facilities were helpful for understanding the function of electrochemical energy converters, their components and materials, particularly when they were under operation. I will focus on my talk on the processes which take at the molecular scale. This includes the redox reactions in solid-liquid interface systems such as in lithium batteries and photoelectrochemical cells, and also the solid-gas systems such as in high temperature fuel cells and gas sensors. These redox reactions are accompanied changes in the transport properties of the materials under investigation. It is therefore interesting to combine x-ray and neutron spectroscopy measurements directly with electroanalytical methods. Latter include seemingly simple I/V curves and the somewhat more sophisticated impedance measurements, which allow to assess the charge carrier dynamics in the energy converters. I will also present some experiments which had the aim to look into the microstructure and mesostructure of electrodes and electrolytes. Of particular interest is a recent resonant SAXS study carried out on an SOFC electrode assembly at and by the Advanced Photon Source (UNICAT) in Argonne Lab.

Resume : The complete understanding of the functionality of battery components requires the correlation with underlying physical and chemical properties which is the challenge for most analytical methods due to a lack of reference materials. For this purpose, PTB implemented physically traceable methods based on X-ray spectrometry. Lithium Sulfur (Li-S) batteries are promising candidates for improved high capacity batteries, but the cycling stability of currently developed Li-S cathode materials is limited due to undesired side reactions and occurring polysulfides. With sulfur K-edge near absorption spectrometry (NEXAFS) for the cathode done under protective argon atmosphere we get access to the oxidation state of sulfur and therefore we can identify the polysulfides for different states of charge (SOC) and states of health (SOH) of a battery. NCM based LIBs are well working systems and under steady development. Some degradation processes of the cathode results in the deposition of manganese at the separator and the graphite anode. With reference-free X-ray fluorescence spectrometry we can quantify the mass deposition of manganese on the anode and the separator. With additional manganese K-edge and L-edge NEXAFS we also can conclude to the present species of manganese. To investigate fluid systems such as electrolyte solutions we designed in collaboration with TU Berlin a fluid cell with a 150 nm thin silicon nitride entrance window that enables soft X-ray studies to probe even light elements such as fluorine. With the fluid cell we can investigate the different behavior of Ionic Liquids in the present of lithium hexafluorophosphate. For further steps, and in collaboration with TU Berlin, an in-situ and in-operando cell is under construction. With that and the combination of simultaneous Galvanostatic Cycling with Potential Limitation (GCPL) and XAS measurement capabilities we can get access to the link between material properties and battery behavior (functionality).

Resume : Research and development in the field of lithium ion batteries (LIBs) is facing continuously increasing demands concerning an enhanced energy density, a long cycle life, and improved safety properties for the vast diversity of applications ranging from portable electronic device to electric vehicles. Since a LIB is a highly complex system in which numerous effects occur simultaneously during electrochemical cycling, it is necessary to apply suitable analysis methods to understand the progression of detrimental effects that can affect the electrochemical performance. Amongst others, the dissolution of transition metals from the positive electrode into the electrolyte can cause severe degradation effects on the surface of the graphitic negative electrode. Specifically the dimensions of the deposits in the lower nanometer-scale and the small amounts of dissolved/deposited species require sophisticated analysis methods which are capable of detecting these species with a high lateral resolution and/or low detection limits. State-of-the-art active materials for the positive electrode are based on layered transition metal oxides like LiNixCoyMnzO2 (x+y+z=1, NCM) due to a good capacity retention and rate capability. However, high current densities can lead to local overcharge conditions that facilitate the dissolution of transition metals into the electrolyte. The dissolved species can either re-deposit on the surface of the NCM particles or interact with the solid electrolyte int

Resume : Nowadays, ionic liquids (ILs) are in the center of attention for different chemical applications, for example, as catalysts for chemical reactions or as electrolyte in lithium ion batteries. For this reason, it is necessary to know in detail the decomposition products of ILs. So far, the degradation of ILs were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) or theoretical calculations [1]. Only few studies deal with the investigation of decomposition products via chromatographic methods. We have developed and optimized new ion chromatography (IC) and capillary electrophoresis (CE) methods to analyze and identify cation and anion degradation products of different ILs [2, 3]. The investigated ILs were pyrrolidinium- and imidazolium- based cations and as anion trifluoromethanesulfonyl imide (TFSI) and fluorosulfonyl imide (FSI) have been used. It has been found out that FSI degraded when it was mixed with electrolyte salts like lithium hexafluorophosphate, while TFSI did not. Additionally, the fluoride concentration in different aged ILs was quantified by CE with conductivity detection. These results were confirmed by independent fluorine K-edge X-ray absorption spectrometry (NEXAFS) investigations using an ultra-high vacuum compatible fluid cell with a 150 nm thin Si3N4 window. The samples are also measured as dried droplet depositions on Si wafer substrate. 1. Chambreau S D, Boatz J A, Vaghjiani G L, Koh C, Kostko O, Golan A, and Leone S R, Thermal Decomposition Mechanism of 1-Ethyl-3-methylimidazolium Bromide Ionic Liquid. The Journal of Physical Chemistry A, 2011. 116(24): p. 5867-5876. 2. Pyschik M, Kraft V, Passerini S, Winter M, and Nowak S, Thermal Aging of Anions in Ionic Liquids containing Lithium Salts by IC/ESI-MS. Electrochimica Acta, 2014. 130: p. 426-430. 3. Pyschik M, Klein-Hitpaß M, Girod S, Winter M, and Nowak S, Capillary electrophoresis with contactless conductivity detection for the quantification of fluoride in lithium ion battery electrolytes and in ionic liquids—A comparison to the results gained with a fluoride ion-selective electrode. ELECTROPHORESIS, 2016: p. n/a-n/a.

Resume : GeSbTe is an interesting new material being developed for non-volatile memory devices, and nitrogen doping is used to increase device reliability. We report here on metrology issues impacting the robustness of the process, these include: technology transfer between fabs and the establishment of reliable calibration protocols. WD-XRF (wavelength-dispersive X-ray fluorescence) can be used to obtain quite precise indications of the sample stoichiometry, and standard calibration methods yield good reproducibility between measurement sites for the indicated content of the heavy elements. However, the reproducibility of the indicated N content is rather poor, probably due to an unexpected sensitivity to different calibration protocols. Moreover, the Fundamental Parameters method used to reduce the XRF data does not have direct metrological traceability for the absolute values obtained. Therefore a set of reference samples was measured using elastic backscattering spectrometry (EBS), one of the “Ion Beam Analysis” (IBA) techniques [1]. Using EBS and a 3.7 MeV alpha particle beam the backscattering signal for the heavy elements is Rutherford (where the reaction cross-section is known analytically), but the backscattering yield for N is strongly enhanced by a nuclear resonance. The 14N(a,a)14N scattering cross-section function has been determined by Gurbich et al [2] using a nuclear model of the scattering event fitted to backscattering yield data, and we have checked it directly against RBS of a 200 nm SiNx thin window. We therefore directly compare the precise XRF-WDX data with the accurate IBA data, noting that metrological traceability has recently been demonstrated directly for RBS (Rutherford backscattering spectrometry, a special case of EBS) [3]. We also compare XRF WDX with PIXE (particle-induced X-ray emission, another IBA technique entirely comparable to XRF except for the excitation mechanism), and draw conclusions on the establishment of XRF (and PIXE) reference standards for this material system. [1] C. Jeynes, J.L. Colaux, Thin film depth profiling by Ion Beam Analysis, Analyst 141 (2016) 5944–5985 [2] A. F. Gurbich, I. Bogdanović Radović, Z. Siketić and M. Jaksić, Measurements and evaluation of the cross-section for helium elastic scattering from nitrogen, Nucl. Instrum. Methods B, 2011, 269, 40–44 [3] C. Jeynes, RBS as a new primary direct reference method for measuring quantity of material, Nucl. Instrum. Methods B, 2017 (in press) http://dx.doi.org/10.1016/j.nimb.2016.11.041

Resume : X-ray spectrometry is a widely used non-destructive method for the investigation of various materials in many fields of research important for addressing the main global challenges in Energy, Health, Environment and Mobility as well as for the preservation of Cultural Heritage. X-ray fluorescence techniques are used qualitatively as well as quantitatively for sensitive and simultaneous elemental detections. Changing the geometry to very low incident angles (TXRF) is employed for surface analysis, and shallow incident (GIXRF) or emitting (GEXRF) angles allow for depth dependent investigations. By the use of focusing devices (µ-XRF), 2D and 3D mappings are made possible for locally resolved structural characterization. Wavelength-dispersive (WDXRS) systems will provide a higher energy resolution for the detection of fluorescent radiation compared to energy-dispersive systems (EDXRS). Complementary to these techniques, emission and also absorption spectroscopies ((N)EXAFS, XANES) enable for chemical speciation. Here, we will give an overview over recent and upcoming conferences and networking events, which are aiming at fostering the collaboration between different X-ray Spectrometry groups in Europe.

Resume : In its active mode, scanning thermal microscopy (SThM) allows the local thermal characterization of materials. This can be done by measuring the electrical response of a resistive probe during its controlled heating while in contact with the sample surface [1]. Nevertheless, obtaining accurate measurements is very challenging because of the complex probe-sample interaction occurring at nanoscale. Indeed this interaction takes place through various heat transfer channels and is strongly dependent on parameters such as the size, geometry and surfaces of probe and sample [2-3]. We developed a calibration method for thermal conductivity measurement using specimens of well-known thermal conductivities and controlled surfaces to perform the thermal measurement of an unknown sample. Two different surrounding environments were considered and three probes with different sizes and sensor materials were used. We performed local-point SThM measurements and studied the changes of the electrical probe resistance as a function of the sample thermal conductivity. Ultimately results were shown to be strongly dependent on the environment and probe, and smaller probes are more sensitive to the tip-sample contact physical parameters. References: [1] S. Gomés et al., PSSA 212, 3 (2015) [2] Y. Ge et al., Nanotech. 27, 32 (2016) [3] F. Menges et al., RSI 87, 7 (2016) Acknowledgements: The research leading to these results has received funding from EU project FP7-NMP-2013-LARGE-7 QUANTIHEAT.

Resume : Scanning Thermal Microscopy (SThM) experiments are increasingly performed under vacuum conditions. Such environmental conditions enable to reduce the thermal channel number by which the probe-sample heat flux may be transferred. Then a simplification of the modeling used to interpret measurements is possible, the spatial resolution of the method is improved and the investigation of thermal conduction at solid-solid mechanical nanocontacts [1, 2] and near-field radiation [3] is facilitated. However the tip wear and its contamination resulting of the repeated scanning displacements of the probe over the sample surface during the acquisition of an image as well as the sample surface are parameters to be considered. Considering all these fundamental and technical issues, we developed a combined SThM/Scanning Electron Microscopy (SEM) instrument enabling the real-time observation and characterization of the shape and size of the tip, and of the surfaces during SThM measurements. We present our instrument and report on the analysis of measurements and imaging of reference and nanostructured samples by means of this new instrument equipped with various resistive SThM probes operating in active mode. References: [1] Gomès S. et al., Physica Status Solidi (a), Vol. 212, Issue 3/2015, page 477–494. [2] Gotsmann B. et al., Nanotechnology, 2010. [3] Kittel A. et al., Physical review letters, 2005, 95, 224301. Acknowledgements: The research leading to these results has received funding from EU project FP7-NMP-2013-LARGE-7 QUANTIHEAT.

Resume : Photothermal radiometry (PTR) techniques are suitable non contact methods to determine thermal properties of thin film material (from few nanometers to few micrometers thick). A sample is first heated to a specified temperature in a furnace then it is thermally disturbed by a known laser beam excitation. The thermal properties of the sample are determined by inverse method by comparing the obtained experimental thermal response to a thermal diffusion model. As thermal properties depend on temperature, it is essential to accurately ascertain the temperature of the sample during the test, especially at the time of the thermal excitation. This temperature is measured thanks to a non-removable thermocouple sealed in the furnace in close vicinity of the sample. Even if PTR is a non contact method, the temperature measurement is disturbed by the power deposited by the laser beam at the front face of the sample. For that reason, LNE has developed an original method for the in-situ temperature calibration of the measurement thermocouple (based on the melting of reference materials), as well as a specific measurement procedure enabling to correct the influence of the power of the thermal excitation on the temperature of test. This paper presents in detail these two procedures. This work was funded through the European Metrology Research Programme (EMRP) Project ENG53 ThinErgy. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

Resume : SThM aims at exploring heat transfer at micro-/nanoscale by the use of an AFM probe. This enables fundamental research for the understanding of thermal science at these scales. Industrials are also concerned since the thermal characterization of structures such as thin films, nano-objects, active integrated devices (MEMS or NEMS)… always requires better methods to reach measurement at the spatial resolution relevant for analysis. Temperature, thermomechanical properties or thermal conductivity may be determined by SThM. Despite an abundant literature on experimental results, there is no proof of traceability for any of them. A reference method for macroscopic traceability of thermal conductivity already exists at LNE. A SThM has been developed within the frame of the European project Quantiheat to establish this traceability at nano-scale. Many steps are required to reach this objective: optimization of the experimental setup, establishment of uncertainty budgets and choice of reference samples for thermal measurements at nanoscale. It is proposed here to describe the experimental setup, the measurement and calibration protocols, and the first developments for the uncertainty analysis. The paper focuses on the expression of the measurement model (linking the experimental measurand and the readings of the setup) and the Ishikawa’s diagram (influencing factors on the measurand). Finally the uncertainty on the experimental measurand is calculated by the Monte-Carlo method.

Resume : The functional properties of nanosystems are governed by quantum size effects and confinement of electrons, spins, phonons, etc. Phonons, described by the phonon density of states (PDOS), strongly influence many material properties, such as thermal, electrical and mechanical processes, as well as superconductivity. Accurate and systematic experimental determination of the PDOS of nanomaterials is therefore essential in order to understand the functionality of such materials. We have investigated the mutual relation between the superconducting critical temperature and the PDOS of Sn nanowires embedded in Al2O3 porous matrices. Bulk Sn is a classical type-I superconductor with a critical temperature of 3,72 K which can be modified by nano-engineering. However, the role of phonon confinement in this modification is still under debate. The PDOS of the nanowires has been determined by nuclear inelastic scattering of synchrotron radiation. Clear changes are observed compared to the PDOS of a bulk sample. The nanowire critical temperature was calculated using the measured PDOS and was compared to the values obtained by electrical resistance measurements. We demonstrate that the modified PDOS of the nanowires leads to an increase of the electron-phonon coupling and of the nanowires? superconducting critical temperature.

Resume : Within the general goal of reaching high operating temperature while maintaining strong requirements on infrared photodetector performances, the pressure on HgCdTe material quality is increasingly growing. In particular, careful attention is now being paid to strain and strain relaxation within HgCdTe photodiodes. While recent studies have focused on the lattice mismatch induced strain over areas in the order of the wafer, no experimental investigation has been able to resolve the strain at the micrometer level. The typical millimetric spatial resolution limit of standard diffraction can be overtaken using a focused synchrotron X-ray white beam. Indeed, by performing submicronic Laue diffraction measurements, we can map with a sub-micrometer resolution both the local deviatoric strain and lattice orientation. This work focuses on the analysis of etched trenches inside HgCdTe layers with variations on passivation and annealing steps. We are able to investigate a precise mapping around the etching and appreciate the local effects of the processing steps. Diffraction peak displacement mapping evidences bending of the crystal planes around etched trenches, with strong dependence upon the processing steps. The passivation step leads to sufficient strain for plastic deformation to occur at the lateral edges of the etching. The annealing step is found to have a healing effect on the layer, which reduces the overall deformation and even re-crystallizes plastically deformed area.

Resume : Interfaces of heterogeneous solids, ranging from polycrystalline materials to composites, are frequently encountered in nanotechnology. Electron transport in these heterogeneous materials and across their interfaces with other solids critically depends on the energy barriers electrons encounter on their way. Because of structural heterogeneity, the barriers may exhibit significant spatial variations resulting in a broad distribution of heights and built-in potentials. Quantification of the distributed interface barriers represents a formidable experimental challenge since direct association of interface properties with those of a surface is generally inaccurate. Here we present a methodology enabling quantification of electron barrier heights at interfaces of laterally inhomogeneous semiconductors and metals with insulators in metal/insulator/metal or metal/insulator/semiconductor structures using the field-dependent Internal Photo-Emission (IPE) of electrons. Experimental examples deal with interfaces of technologically-relevant materials including metallization stacks, e.g., Hf/CuTe electrodes, as well CuTe and GeSe alloys on top of insulating oxides (Al2O3, HfO2, SiO2) used in microelectronics. We will show that these interfaces contain “patches” with differences in barrier height (or the effective work function) of up to 1 eV which makes the electrode heterogeneity a crucial factor in designing electron devices suitable for low-voltage operation.

Resume : Nucleation of oxide precipitates in highly B-doped CZ silicon is enhanced compared to moderately B-doped wafers. Because of the very high density of nuclei it can easily happen that the interstitial oxygen is consumed before the oxide precipitates exceed the detection limit of common analysis techniques like preferential etching. In this work, we applied different analytical techniques like scanning transmission electron microscopy (STEM), reactive ion etching (RIE) and cleave and etch techniques to characterize nanometer sized oxygen precipitates. The samples used in the experiment were first annealed at 780°C for 3h to stabilize precipitate nuclei and then these nuclei were grown at 1000°C for 0, 0.5, 1, 2, 16, 32 and 64h. The size distribution, morphology, and density of the oxide precipitates were determined by STEM. The composition of the precipitates was investigated by energy dispersive x-ray spectroscopy (EDX) and electron energy loss spectroscopy (EELS). Moreover, reactive ion etching (RIE) and cleave and etch (C&E) techniques were used to detect oxide precipitates. Here, preferential etchants with different sensitivity were compared. RIE is suitable for detection of oxide precipitates because of their masking effect based on the available high oxide to silicon selectivity. By the investigation of the size distribution of oxygen precipitates, we were able to elucidate their growth behavior. EDX and EELS studies helped to find out if considerable amounts of boron are incorporated into the oxide precipitates for strain relaxation.

Resume : To get independent from a material artefact definition of the mass unit kg, there is an international aim to find a definition based on fundamental constants. The new definition of the kilogram will be based on the Planck constant. One way to define a fixed value for the Planck constant is based on the Avogadro constant. Hereby, the exact definition of the Avogadro constant is achieved by “counting” the silicon atoms in a one kilogram silicon sphere. For the quantitative surface characterization of such a monocrystalline silicon sphere PTB has constructed and taken into operation an analytical instrumentation, which combines X-ray fluorescence and X-ray photoelectron spectroscopy techniques. The main objective of this instrumentation is the characterization and quantification of the oxide layer, which is in the order of a few nanometers, and unintentional contaminations, e.g. from hydrocarbons. The novel instrumentation is equipped with a ball manipulator allowing to measure at any point on the surface of spherical samples with a diameter of about 93.6 mm and additionally of reference samples. Applying complementary X-ray methods for quantitative surface characterization allows for minimizing the influence of the surface of the silicon sphere on the total uncertainty budget for the determination of the Avogadro constant. R. Fliegauf, B. Beckhoff, E. Beyer,E. Darlatt, I. Holfelder, P. Hönicke, G. Ulm, M. Kolbe: Surface characterization of silicon spheres by combined XRF and XPS analysis for determination of the Avogadro constant. DOI: 10.1109/CPEM.2016.7540797

Resume : Radio frequency (rf) glow discharge optical emission spectroscopy (GDOES) instruments have seen significant development in recent years, and have seen application for diverse thin film analyses. In addition, the use of a pulsed source has increased depth resolution, now down to the nanometer scale. However, the new application domains require further investigation to improve accuracy and understanding of the films. In this contribution, pulsed rf-GDOES was used to determine the chemical composition and thickness of SiO2 thin films on Si substrates deposited by plasma enhanced atomic layer deposition (PEALD). The use of a pulsed source and high acquisition rates allowed nm-scale resolution for such layers, whose thickness was ~ 150 nm. The films thickness was calculated from the GDOES oxygen profiles, and it is in agreement with ellipsometry and X-ray reflectivity measurements. The intensities of the H, N and C concentrations in the films correspond well to different conditions of the applied plasma power during film deposition. Moreover, the total sputtering time until the SiO2/Si interface was ~ 13 s, much shorter than the analysis time of alternative techniques for thin film analysis, e.g. secondary ion mass spectrometry. The findings of this study thus validate the use of pulsed rf-GDOES for analysis of PEALD SiO2 thin films, where measuring the chemical composition is required for thoroughly understanding the effect of plasma power conditions on the PEALD thin film.

Resume : EMPIR Joint Research Project “3D Stack” involving 9 partners from 6 European countries, including 5 NMIs, started one year ago and has the objective to develop traceable measurement capabilities for structural and chemical defects inspection in high aspect ratio through silicon vias (HAR TSVs) and wafer/chip bonding and thinning and accurate measurement techniques for thermal and electrical materials characterisation at the nanoscale of the TSVs. Updated information on the ongoing work that will be given during the Symposium is related with the development of new and improved measurement set-ups and several types of measurement techniques applied to HAR TSVs and control of wafers/dies bonding and thinning. Indeed, a lock-in thermography set-up for the calibration of Scanning Thermal Microscopy measurements and a novel 3D-AFM with different measurement strategies for non-destructive measurements of dimensional properties of TSVs, have been developed. A high speed large range metrological AFM for dimensional characterisation of wafers has also been developed and improved for bonding/thinning process control. Different characterizations and measurements have been carried out on different types of samples produced by part of the project partners (samples with Cu filled TSVs, with or without voids, cross-sectioned and polished, bump arrays and assembling of 3D flip chip stacks): dimensional and structure characterization on cross-sectioned TSVs using AFM, SEM and light microscopy

Resume : Secondary ion mass spectrometry depth profiling using argon gas cluster sputtering is increasingly applied for the analysis of organic materials including layer stacks used in organic electronic devices. The depth profiles provide valuable information about layer diffusion, segregation, chemical degradation and contaminants in the stack but are generally not quantitative. We report a study of the quantification of the amount of matter by secondary ion mass spectrometry (SIMS) when depth profiling a nominally 3.1 nm delta layer of fmoc-pentafluoro-L-phenylalanine in Irganox 1010. The depth profiles are made using 5 keV Ar2300+ sputtering with analysis by 25 keV ions. Data for 89 negative secondary ions shows profiles whose integrated areas, when normalized to the intensity for the pure material, vary over a factor of 12. This variation mainly arises from matrix effects that are measured here using separate samples with mixed layers of 3 intermediate compositions of the two materials. Strong effects can cause the delta layer signal to show structure that may be misinterpreted. The compositional profile is established by using trial profiles, representing the composition, which are then enhanced or reduced according to the measured matrix effect and the result is fitted to the normalized intensity data. It is critical to include the roughening caused by the ion beam. When this is included, the amount of matter is found to be equivalent to 3.25 ± 0.05 nm. It is concluded that the matrix terms used are a good description of the phenomenon and that SIMS profiles may be made quantitative if suitable secondary ions are available and the matrix terms measured.

Resume : Our understanding of the physical phenomena taking place in Nature often requires extracting information from different types of wavefields. Optical fields are special in this sense because they are of infinite-range, like all electromagnetic waves, and can carry information on events that happened remotely in space and time. Secondly, scattered light gives us insights on the structure of matter due to the fact that most of the electronics and molecular transitions fall in the ultraviolet, visible and infrared range of the electromagnetic spectrum. Currently, an exciting challenge for optical metrology is offered by nanotechnology where objects' features keep on shrinking and new materials, with unprecedented properties, are realized. Because of this, regardless of how good spatial resolution, accuracy and precision of current optical methods are, novel ways to improve them have to be continuously found. Additionally, high-tech industrial applications set also stringent requirements on speed, non-invasiveness and integration on the said methods. In this talk, with the help of few applications coming from renewable energy, semiconductor industry and space research sectors, we will present some of the current efforts, and future concepts, for quantitative measurements of physical properties of materials and characterization of geometrical parameters of objects at sub-nanometer precision.

Resume : Considerable attention was given to ZnO and ZnO-related materials as they proved to be highly efficient, low-cost and non-toxic transparent conductive oxides (TCOs) suitable for large area applications for photovoltaics. In the present work, Al and Ga doped ZnO thin films deposited on oxidized Si substrates are characterized using variable angle spectroscopic ellipsometry; additional optical and non-optical techniques were employed to confirm and support the ellipsometric models considered. The samples were obtained by means of pulsed chemical vacuum deposition (CVD) and atomic layer deposition (ALD). As known from previous studies [1,2] the presence of dopants in ZnO thin films generally induce significant changes in the optical, electrical and morphological properties. We present our findings for a series of Al and Ga doped ZnO layers with different concentrations of the dopants, discussing their influence on the optical and morphological properties. Additionally, the changes determined by the thickness variation of the TCO layer are reported. References [1] F.K. Shan, Y.S: Yu, Thin Solid Films 435, 174 (2003) [2] P. Petrik, B. Pollakowski, S. Zakel, T. Gumprechta, B. Beckhoff, M. Lemberger, Z. Labadi, Z. Baji, M. Jank, A. Nutsch, Applied Surface Science 281, 123 (2013)

Resume : Accurate ellipsometry characterization of non-perfect thin films and nanostructured surfaces are challenging. Imperfections like surface roughness make the associated modelling and inverse problem solution difficult due to the lack of knowledge about the imperfections on the surface. Combining measurement data from several instruments increases the knowledge of non-perfect surfaces. We have used ellipsometry to measure the optical properties of CGS solar cells and confocal microscopy to measure the surface roughness. The ellipsometry measurements are affected by the large surface roughness and the mixed material composition of the CGS solar cells. We investigate the ability of the Rayleigh-Rice (RR) and the Bruggeman effective medium approximation (EMA) method to describe the influence of surface roughness on CGS solar cells. The simulated data obtained from the RR and EMA models is compared with the measured CGS ellipsometric data and it is demonstrated that the RR method gives the best description of the measurements.

Resume : The Keysight Scanning Microwave Microscope (SMM) consists of an atomic force microscope (AFM) interfaced with a vector network analyzer (VNA) allowing to measure complex materials properties of nano-electronics devices. The SMM operates at broadband frequencies between 1-20 GHz. Here we present novel calibration workflows for complex impedance and doping density imaging of semiconducting materials. We show applications to silicon devices and multijunction GaAs solar cells. The calibration workflows are presented as well as the improvement of SMM to get high signal-to-noise ratio. Due to the measurement at high frequency laborious realization of back electrode contacts is not required; this makes it an easy applicable tool for electrical characterization of nanodevices. Due to the capability of the electromagnetic wave to penetrate the surface of the sample under study the technique can be used to selectively sense sub-surface features. In summary, we present an extended SMM for advanced voltage and impedance spectroscopy and novel RF calibration workflows that can be applied to nanoscale semicon devices. SMM results are compared to 3D finite element modeling using Keysight software EMPro.

Resume : In Scanning Microwave Microscopes (SMM) an atomic force microscope (AFM) operating in contact mode is interfaced with a vector network analyzer (VNA). An SMM is thus able to simultaneously measure topography and complex material properties on the nanoscale. The VNA generates microwaves in the range 0.5 - 50 GHz, which are transmitted to the AFM tip via coaxial line and an impedance matching network. Depending on the impedance forming at the tip-sample interface, a fraction of the microwaves is reflected and detected by the VNA in terms of scattering parameter S11. Operation in the microwave regime with fields confined to the tip’s apex allows for spatial resolution typically around 50 nm as well as subsurface sensing. To enable extraction of dopant densities from semiconductor samples we present a fast and versatile algorithm based on classical VNA calibration. This algorithm models the influence of dopant density on tip-sample capacitance thus allowing nanoscale determination of dopant concentrations. As a proof-of-principle we present SMM results on an MBE-grown n-doped GaAs multilayer structure with dopant densities ranging from (1e16 - 6e18) cm^-3 which are then compared to Secondary Ion Mass Spectroscopy (SIMS) data. Furthermore we demonstrate the SMM’s capability to resolve the structure of a nanoscale GaAs-pn-junction.

Resume : Multi-junction solar cells consisting of serially connected, epitactically grown solar cell junctions from III-V materials find broad application as power sources in space as well as in terrestrial concentrator photovoltaics. Due to their electrical interconnection the determination of the spectral responsivity of each sub cell is not trivial. Methods for the relative measurement of the differential spectral responsivity of each sub-junction are well established, but the determination of the absolute spectral responsivity at defined irradiance levels remains challenging. In this presentation we show that by the application of a modified laser-based differential spectral responsivity setup the absolute spectral responsivity and hence the photocurrent at defined irradiance levels can be determined with a low measurement uncertainty. Since the results are also transferable to innovative photovoltaic devices this method could support in future the quantitatively examination of tandem structures in organic or nano-enhanced photovoltaic devices.

Resume : Spectroscopic ellipsometry is a reflectometry experiment with polarised light. The method is very sensitive and fast, making it very popular in optics and solid state physics. In principle, ellipsometry is very suitable for industrial applications. Apart from the classical determination of layer thicknesses and refractive indices, many further properties of solid materials are today probed by this method. This has generated the need for a more thorough investigation of the metrological properties of reflectometric methods like ellipsometry. In this work, we consider the possibilities of traceable results in reflectometric model-based methods and develop a method for generating realistic result uncertainties. Examples for the usefulness of a new method for determining result uncertainties will be given.

Resume : We report results of TEOS (Tip Enhanced Optical Spectroscopy, including Tip Enhanced Raman scattering (TERS) and Tip Enhanced Photoluminescence (TEPL)) characterization of functionalized graphene oxide and 2D semiconductors, MoS2 and WS2. In a first part we will present TERS results of graphene oxide flakes including the dramatically enhanced response over wrinkles and creases, as well as over nanopatterns imprinted into flakes using a sharp diamond probe. Then, TEOS characterization of MoS2 and WS2 flakes will be presented. TEPL imaging reveals localized intensity decrease only at center position of the flakes. This spectral variation indicates differences in electronic properties correlated with the number of layers and breaks of translation symmetry, which is further confirmed by TERS, Kelvin probe force and Atomic Force Microscopic imaging. TEOS maps of single and few-layer-flakes of 2D semiconductors show that the spatial distribution of both Raman and PL intensities across the flake varies for different peaks, providing interesting insights into the structure of such 2D semiconductors with 10-20 nm spatial resolution.

Resume : With the explosion of costs at most advanced front end technologies nodes, and consequent end of Moore’s low, packaging area has become a key differentiator to continue sustainability in semiconductor industry. Beside the traditional way to package semiconductor devices based on wire bonding, the so called “Advanced Packaging” is getting momentum due to its extreme flexibility and potential cost reduction. New revolutionary way to interconnect die to die and/or die to wafer, like 2.5D and 3D stacking, are currently under industrialization, and metrology tools to add the process qualification are more and more required. Optical metrology is a powerful tool to allow the control of dimensions from micro to nanometer scale. Low coherence interferometry was here explored in combination with dual mode Near Infrared Microscopy as a potential in-line process control solution for the Advanced Packaging Area capable of performing topography and tomography down to nanometer level. We will review the different parameters to be characterized and how to proceed to extract them by discussing practical cases. For example, we investigated the effect of the grinding process onto the bow/warpage of the wafer and onto the local nanoscale topography of the surface. We will also develop how our technics have significant impact on process development duration and manufacturing cost.

Resume : Here we present a review study on oblique-incidence spectrophotometric measurement techniques for reliable determination of optical parameters of thin-film coatings. The characterization methods and instrumentation for obtaining experimental results for the optical parameters and thickness of thin-film samples such as ZnO are presented. These results are based on spectral reflectance data at multiple angles of incidence including 10 and 45. The optical parameters of the ZnO coatings on thermally grown SiO2 on silicon substrate derived from the reflectance results are compared with those determined from ellipsometric measurements. Preliminary results indicate that the characterizations are consistent and agree well for the nominal film thicknesses of 20 nm and 200 nm. The consistency among the determined optical parameters of thin-film single layers using a purpose-built gonioreflectometer and a commercial ellipsometers used in an earlier study [1] confirmed the accuracy of the spectrophotometric measurements. [1] S. Pourjamal, H. Mäntynen, P. Jaanson, D. Rosu, A. Hertwig, F. Manoocheri, and E. Ikonen, “Characterization of thin film thickness,” Metrologia 51, S302–S308 (2014).

Resume : It is known that the properties of a SWCNT depend largely on its chiral structure, termed “chiralities”, identified by two integers n and m describing the “roll-up” vector of a graphene lattice to form the SWCNT. Thus, the chirality distribution of a SWCNT sample plays key roles in determining the properties and directing its commercial applications. In 2013, The National Institute of Standards and Technology (NIST) in the United States released the world's first reference material RM8281 for dispersed single-walled carbon nanotube (SWCNT). However, the accompanying User Information doesn’t include chirality distribution, which is known as one of the most important structure parameters. Here, we present for the first time a quantitative chirality assessment of the RM8281 by using an enhanced method for UV-VIS-NIR absorption spectrum (AS) analysis. Our results show that approximately 75 % of SWCNTs in RM8281 have a diameter in the narrow range of 0.7 - 0.9 nm, and ≈ 69 % of SWCNTs have a chiral angle from 15° to 30°. Of significance, ≈ 25 % of the total RM8281 SWCNT population was found to be the (6,5) species nanotubes. Transmission electron microscopy and electron diffraction techniques were employed to validate the AS analysis. An adequate statistical analysis on nearly three hundred individual and bundle RM8281 SWCNTs, present a solid statistic of structure distributions: diameter, chiral angle, chirality and S-/M-SWCNT ratio. An excellent agreement between spectroscopic and microscopic techniques suggests that the extended AS analysis approach could be employed as a standard protocol for determining the chirality population of a SWCNT sample. Importantly, the census of the chirality population in the RM8181 sample fill in the gap of the missing structure information in the world´s first reference material of SWCNT, thus, will largely push forward its wide applications.