Resolving depth gradients of microstructure and residual stresses within individual sublayers of multilayered thin films and understanding their origin as well as their influence on functional properties are challenging tasks. In this work, a newly developed synchrotron focusing setup based on Multilayer Laue Lenses, providing an X-ray beam diameter of ∼30 nm, is used to characterize the cross-sectional properties of a 2.9 μm thick sculptured multilayered TiN-SiOx film, which consists of twelve ∼230 nm thick nano-crystalline TiN sublayers of zigzag columnar grain morphology separated by eleven amorphous SiOx sublayers, both prepared by oblique magnetron sputtering on a Si(100) substrate. The X-ray nano-diffraction analysis of the TiN sublayers reveals (i) an oscillatory variation of compressive residual stresses across the film ranging between −1.8 and −0.25 GPa, (ii) the presence of <100> fiber textures with three different fiber axis orientations, which abruptly change between the individual sublayers, and (iii) gradually decreasing densities of structural defects within every TiN sublayer, exhibiting a sawtooth-like depth-profile across the film. The near-substrate TiN sublayer shows the highest compressive stress reaching ∼ −1.8 GPa, a unique texture and the largest density of defects among all sublayers, which indicates diverse nucleation mechanisms of TiN on the native Si oxide and on the SiOx sublayers. The results demonstrate that the average stress state and the microstructure within the individual TiN sublayers can be influenced effectively by the applied deposition conditions, although self-organization processes during the sublayers' evolution give rise to the occurrence of qualitatively similar gradual trends, which differ in intensity and which were characterized also by complementary laboratory X-ray diffraction, as well as scanning and transmission electron microscopies. Finally, the presented results document that the novel X-ray nano-probe approach allows for the characterization of nano-scale gradients within individual microstructural features of polycrystalline thin films and pioneers the way for knowledge-based synthesis of thin films with predefined cross-sectional microstructure and property gradients.

We investigate the influence of the Mo-layer thickness on the EUV reflectance of Mo/Si mirrors with a set of unpolished and interface-polished Mo/Si/C multilayer mirrors. The Mo-layer thickness is varied in the range from 1.7 nm to 3.05 nm. We use a novel combination of specular and diffuse intensity measurements to determine the interface roughness throughout the multilayer stack and do not rely on scanning probe measurements at the surface only. The combination of EUV and X-ray reflectivity measurements and near-normal incidence EUV diffuse scattering allows to reconstruct the Mo layer thicknesses and to determine the interface roughness power spectral density. The data analysis is conducted by applying a matrix method for the specular reflection and the distorted-wave Born approximation for diffuse scattering. We introduce the Markov-chain Monte Carlo method into the field in order to determine the respective confidence intervals for all reconstructed parameters. We unambiguously detect a threshold thickness for Mo in both sample sets where the specular reflectance goes through a local minimum correlated with a distinct increase in diffuse scatter. We attribute that to the known appearance of an amorphous-to-crystallization transition at a certain thickness threshold which is altered in our sample system by the polishing.

We investigated the growth of Mo/Si multilayers (ML) deposited using a highly collimated flux of ion-beam sputtered particles for a wide range of deposition angles. Growth of the multilayers at normal and moderately inclined deposition is dominated by surface relaxation resulting in smooth interfaces of the multilayer stack. The first signs of interface roughening are observed at a deposition angle of 45° with respect to the normal to the substrate surface. At an oblique angle of 55°, the ML interfaces undergo fast progressive roughening from the substrate to the top of the ML stack, leading to the formation of ripples which are perpendicular to the deposition flux direction. Deposition of the multilayer at an angle of 65° results in a highly periodic lateral ripple structure with a period of 10 nm. The mature ripple pattern forms during growth of only the first few layers and then stabilizes. The ripples propagate through the whole ML stack with almost no changes in frequency and amplitude, resulting in a highly periodic bulk array composed of silicon and molybdenum nano-rods closely packed in a 6-fold symmetric lattice. We present a simple model for the ripple growth, which gives results that are in good agreement with experimental data.

For the High Energy Density Instrument (HED) at the European XFEL a hard x-ray split-and-delay unit (SDU) is built covering photon energies in the range between 5 keV and 24 keV. This SDU enables time-resolved x-ray pump / x-ray probe experiments as well as sequential diffractive imaging on a femtosecond to picosecond time scale. The set-up is based on wavefront splitting that has successfully been implemented at an autocorrelator at FLASH. The x-ray FEL pulses will be split by a sharp edge of a silicon mirror coated with Mo/B4C and W/B4C multilayers. Both partial beams then pass variable delay lines. For different photon energies the angle of incidence onto the multilayer mirrors is adjusted in order to match the Bragg condition. Hence, maximum delays between +/- 1 ps at 24 keV and up to +/- 23 ps at 5 keV will be possible. Time-dependent wave-optics simulations are performed with Synchrotron Radiation Workshop (SRW) software. The XFEL radiation is simulated using the output of the time-dependent SASE code FAST. For the simulations diffraction on the edge of the beam-splitter as well as height and slope errors of all eight mirror surfaces are taken into account. The impact of these effects on the ability to focus the beam by means of compound refractive lenses (CRL) is analyzed.

Point focusing measurements using pairs of directly bonded crossed multilayer Laue lenses (MLLs) are reported. Several flat and wedged MLLs have been fabricated out of a single deposition and assembled to realise point focusing devices. The wedged lenses have been manufactured by adding a stress layer onto flat lenses. Subsequent bending of the structure changes the relative orientation of the layer interfaces towards the stress-wedged geometry. The characterization at ESRF beamline ID13 at a photon energy of 10.5 keV demonstrated a nearly diffraction-limited focusing to a clean spot of 43 nm × 44 nm without significant side lobes with two wedged crossed MLLs using an illuminated aperture of approximately 17 µm × 17 µm to eliminate aberrations originating from layer placement errors in the full 52.7 µm × 52.7 µm aperture. These MLLs have an average individual diffraction efficiency of 44.5%. Scanning transmission X-ray microscopy measurements with convenient working distances were performed to demonstrate that the lenses are suitable for user experiments. Also discussed are the diffraction and focusing properties of crossed flat lenses made from the same deposition, which have been used as a reference. Here a focal spot size of 28 nm × 33 nm was achieved and significant side lobes were noticed at an illuminated aperture of approximately 23 µm × 23 µm.

We present a concept of a dedicated illumination to perform full-field X-ray microscopy with multilayer Laue lenses at laboratory X-ray sources. The basic idea is the application of a focusing X-ray multilayer mirror as condenser optics to provide a quasi-monochromatic and solid illumination, and consequently optimal conditions for the operation of the multilayer Laue lenses. First experimental results demonstrate the proof of this concept.

Diffractive X-ray optical elements made by thin film coating techniques such as multilayer Laue lenses (MLL) and multilayer zone plates (MZP) are promising approaches to achieve resolutions in hard X-ray microscopy applications of less than 10 nm. The challenge is to make a lens with a large numerical aperture on the one hand and a decent working distance on the other hand. One of the limiting factors with the coated structures is the internal stress in the films, which can lead to significant bending of the substrate and various types of unwanted diffraction effects. Several approaches have been discussed to overcome this challenge. One of these is a three-material combination such as Mo/MoSi2/Si, where four single layers per period are deposited. Mo and Si represent the absorber and spacer in this case while MoSi2 forms a diffusion barrier; in addition the thicknesses of absorber and spacer are chosen to minimize residual stress of the overall coating. Here the diffraction efficiency as well as the profile of the beam in the focal plane are discussed in order to find a tradeoff between lowest residual stress and best diffraction properties.

The throughput of extreme ultraviolet (EUV) lithography systems is presently strongly limited by the available radiant power at the wafer level. Besides increasing the power of EUV sources, also the quality of the optical elements plays a key role. With state of the art multilayer mirrors the main cause of diminished reflectance is surface and interface roughness as well as interface diffusion. Both properties lead to reduced specular reflectance while only the interface roughness causes diffuse scattering. EUV diffuse scatter thus allows to selectively assess the contribution of the interface roughnessThe intensity distribution of diffusely scattered EUV radiation provides information on vertical and lateral correlations of the surface and interface roughness through the appearance of resonant diffuse scattering (RDS) sheets. The study of off-specular scattering thus serves as a natural tool for the investigation of the roughness of the interfaces. However, upon near-normal incidence impinging EUV radiation, dynamical scattering contributions from thickness oscillations (Kiessig fringes) lead to Bragg lines which intersect the RDS sheets. This causes strong resonant enhancement in the scatter cross section which we called "Kiessig-like peak" in analogy to the well known phenomenon of Bragg-like peaks appearing in hard X-ray grazing incidence measurement geometries. Thus for power spectral density studies of multilayer interface roughness, resonant dynamical scattering cannot be neglected. Theoretical simulations based on the distorted-wave Born approximation enable to separate dynamic features of the multilayer from roughness induced scattering. This allows to consistently determine an interface power spectral density (PSD). We have analyzed magnetron sputtered high-reflectance Mo/Si multilayer mirrors with different nominal molybdenum layer thicknesses from 1.7 nm to 3.05 nm crossing the Mo crystallization threshold.Our off-specular scattering measurements at multilayer samples were conducted at the PTB-EUV radiometry beamline at the Metrology Light Source (MLS) in Berlin. The samples were produced by magnetron sputtering and pre-characterized by K, X-ray reflectivity at Fraunhofer IWS, Dresden.

In this work, the process technology for fabricating reactive multilayer systems (RMS) has been developed, and the application of reactive bonding on the assembly of micro systems has been demonstrated. RMS have been fabricated by physical vapor deposition and have been provided as foils as well as direct coatings on the bond partners. Alternatively, RMS coatings by electroplating have been demonstrated. Besides the already established Al/Ni-RMS, new reactive materials as Zr/Al/Si, Pd/Sn and Pd/Al have been evaluated for the bonding process. For structuring the RMS chemical etching, lift-off-techniques, and laser structuring have been used on chip-scale as well as on wafer level up to 8 inches. As application examples, where the high thermal conductivity of reactive bonds is very useful, the mounting of Peltier coolers could be demonstrated. Furthermore, silicon-based acceleration sensors showed low mechanical stress after reactive bonding on ceramic substrates.

The application of thin film coating processes for the fabrication of diffractive X-ray optical elements like sputteredsliced zone plates or multilayer Laue lenses (MLL) is a very promising approach for X-ray focusing down to spot sizes of < 10 nm. However, for practical useful focal length in the order of several millimeters or a few centimeters, multilayer thicknesses of several 10 μm up to a few 100 μm are necessary in order to have large enough numerical apertures of the lenses. Currently one of the main challenges is to coat low-stress multilayers with large total thicknesses in the order of 100 μm. Usually sputter deposition results in thin films with significant compressive stress. With new material combinations such as Mo/MoSi2/Si/MoSi2 and W/WSi2/Si/WSi2 the overall stress can be reduced to almost zero if the individual thicknesses are properly adapted. In the case of these four-layer-systems only the period thickness dp follows the zone plate law. In case of Mo/MoSi2/Si/MoSi2, stress-free multilayers are obtained with dMo = 0.5*dp, dMoSi2 = 0.16*dp and dSi = 0.34*dp.

Diffractive optics for hard X-rays feature superior properties in terms of resolution and efficiency, if volume diffraction effects are exploited all-over the aperture. For multilayer Laue lenses, preferably a wedged geometry is required to obtain this effect. We present an approach utilizing an additional stress layer to realize the necessary geometrical modifications where each lens can be customized to a selected photon energy independently of the given multilayer deposition. The quality of the deposition of the stress layer is evaluated using a laboratory X-ray microscope prior to its application at synchrotron radiation facilities with a special approach to measure the relative layer tilt at high spatial resolution.

Nanoparticles (NPs) can improve mechanical properties of construction elements. However, the integration is not trivial due to the nanoscopic nature of the particles and the different material properties of particle and device: new processing routes have to be found for homogeneous incorporation. Therefore, a wet chemical synthesis is established to incorporate various ceramic NPs such as TiO 2 , TiC, SiC, and WC in copper films in desired concentrations. Depending on the kind and concentration of NPs, hardness and wear resistance of copper are enhanced. The resulting metal matrix composite films are thus of high interest for various applications such as reinforced electrical contacts and in aerospace and automotive technology. The energy released in an exothermic reaction of a reactive multilayer system (RMS) can be used as a precise and well‐defined local heat source for joining the surface of polymers. In this case, a RMS consisting of alternating layers of nickel and aluminum is used. The design of the RMS is adjusted in a way that despite the intensive but very short reaction no damaging of the polymers occurs. The joining process takes only milliseconds and does not require any pre‐ or post‐treatment of the polymers. With the optimal joining parameters, e.g., the joining load, for fiber non‐reinforced polymers tensile strengths can be achieved, which lead to a material failure by tensile attempts. Preliminary tests of fiber reinforced polymers result in a tensile strength that is characteristic for adhesive polymer bonding. Model simulations show that only the first few micrometers of the materials surface are in a liquid state for a very short period of time. In addition to the applied joining load, the materials composition and specifically the resulting solidification process of the liquid polymer phase result in a strong bond between polymer samples that have to be joined. Materials with different thermal expansion coefficients are difficult to join thermally. Among them is the joining of solar cells. It is conventionally carried out by heating the whole assembly. Due to the thermal differences between tabbing wire and silicon, deformations as well as changes in the microstructure can occur. In the worst case, damage of the whole assembly is possible. Upon inspection of the joining process, the high energy consumption of the process itself is also critical.

A tunable two-color multilayer Bragg coating capable of simultaneously reflecting the fundamental and the third harmonic of an x-ray free-electron laser at the same angle and with high reflectance R>0.70 is presented. The novel coating will enable two-color x-ray pump/x-ray probe experiments. This mirror consists of a Si substrate that is coated with two different types of multilayer systems, Mo/B4C layers with a periodicity of d=3. nm directly on the substrate and Ni/B4C layers with a periodicity of d=11.85 nm on top. Fundamental radiation with photon energies between 3 and 9 keV is reflected by a Ni/B4C multilayer system while the third harmonic (9 keV<hν<27 keV) passes this system and is reflected by the Mo/B4C multilayers. The principle has successfully been proven at the beamline BM05 at ESRF.

Energy conversion and storage has become the main challenge to satisfy the growing demand for renewable energy solutions as well as mobile applications. Nowadays, several technologies exist for the conversion of electric energy into e. g. heat, light and motion or vice versa. Among a large variety of storage concepts, the conversion of electrical in chemical energy is of great relevance in particular for location-independent use. Main factors that still limit the use of electrochemical cells are the volumetric and gravimetric energy density, cyclability as well as safety. The concept for a new thin-film rechargeable battery that possibly improves these properties is presented. In contrast to the widespread lithium-ion technology, the discussed battery is based on the redox reaction of multivalent Al-ions and their migration through solid electrolytes. The ion conduction and insertion processes in the crystalline materials of the suggested cell are discussed under a crystallographic point of view to identify suitable electrode and separator materials. A multilayer-stack of all-solid-state batteries is synthesized by pulsed laser deposition and investigated in situ, i. e. during charge and discharge, by X-ray reflection and diffraction methods. The correlation between crystal structure, morphology and electrical performance is investigated in order to characterize the ion diffusion and insertion process.

For the European x-ray free electron laser (XFEL) a split-and-delay unit based on geometrical wavefront beam splitting and multilayer mirrors is built which covers the range of photon energies from 5 keV up to 20 keV. Maximumdelays between Delta tau = +/- 2.5 ps at h nu = 20 keVand up to Delta tau = +/- 23 ps at h nu = 5 keV will be possible. Time-dependent wave-optics simulations have been performed by means of Synchrotron Radiation Workshop software for XFEL pulses at h nu = 5 keV. The XFEL radiation was simulated using results of time-dependent simulations applying the self-amplified spontaneous emission code FAST. Main features of the optical layout, including diffraction on the beamsplitter edge and optics imperfections measured with a nanometer optic component measuring machine slope measuring profiler, were taken into account. The impact of these effects on the characterization of the temporal properties of XFEL pulses is analyzed. An approach based on fast Fourier transformation allows for the evaluation of the temporal coherence despite large wavefront distortions caused by the optics imperfections. In this way, the fringes resulting fromtime-dependent two-beam interference can be filtered and evaluated yielding a coherence time of tau(c) = 0.187 fs (HWHM) for real, nonperfect mirrors, while for ideal mirrors a coherence time of tau(c) = 0.191 fs (HWHM) is expected.

We demonstrate full-field X-ray microscopy using crossed multilayer Laue lenses (MLL). Two partial MLLs are prepared out of a 48 μm high multilayer stack consisting of 2451 alternating zones of WSi2 and Si. They are assembled perpendicularly in series to obtain two-dimensional imaging. Experiments are done in a laboratory X-ray microscope using Cu-Kα radiation (E = 8.05 keV, focal length f = 8.0 mm). Sub-100 nm resolution is demonstrated without mixed-order imaging at an appropriate position of the image plane. Although existing deviations from design parameters still cause aberrations, MLLs are a promising approach to realize hard X-ray microscopy at high efficiencies with resolutions down to the sub-10 nm range in future.

Most of the currently used reflective coatings for EUV and X-ray mirrors are periodic nanometer multilayers. Depending on the number of periods and the absorption in the multilayer stack a certain band width of the incoming radiation can be reflected. In order to increase the integral reflectance or to accept larger ranges of incidence angles, non-periodic multilayers are needed. With the transition from periodic to non-periodic multilayers new challenges arise for the deposition process. Since the reflectance spectra are sensitive to every single layer thickness a precise coating control and an exact knowledge of the interface reactions are required. Furthermore substrate roughness influences the reflectance spectra. With an advanced coating process using additional ion bombardment during thin film growth the integrated reflectance of broadband mirrors can be conserved even for an initial substrate roughness of about 0.7 nm rms.

For the High Energy Density (HED) experiment [1] at the European XFEL [2] an x-ray split- and delay-unit (SDU) is built covering photon energies from 5 keV up to 20 keV [3]. This SDU will enable time-resolved x-ray pump / x-ray probe experiments [4,5] as well as sequential diffractive imaging [6] on a femtosecond to picosecond time scale. Further, direct measurements of the temporal coherence properties will be possible by making use of a linear autocorrelation [7,8]. The set-up is based on geometric wavefront beam splitting, which has successfully been implemented at an autocorrelator at FLASH [9]. The x-ray FEL pulses are split by a sharp edge of a silicon mirror coated with multilayers. Both partial beams will then pass variable delay lines. For different photon energies the angle of incidence onto the multilayer mirrors will be adjusted in order to match the Bragg condition. For a photon energy of hν = 20 keV a grazing angle of θ = 0.57° has to be set, which results in a footprint of the beam (6σ) on the mirror of l = 98 mm. At this photon energy the reflectance of a Mo/B4C multi layer coating with a multilayer period of d = 3.2 nm and N = 200 layers amounts to R = 0.92. In order to enhance the maximum transmission for photon energies of hν = 8 keV and below, a Ni/B4C multilayer coating can be applied beside the Mo/B4C coating for this spectral region. Because of the different incidence angles, the path lengths of the beams will differ as a function of wavelength. Hence, maximum delays between +/- 2.5 ps at hν = 20 keV and up to +/- 23 ps at hν = 5 keV will be possible.

Two different multilayer Laue lens designs were made with total deposition thicknesses of 48 µm and 53 µm, and focal lengths of 20.0 mm and 12.5 mm at 20.0 keV, respectively. From these two multilayer systems, several lenses were manufactured for one- and two-dimensional focusing. The latter is realised with a directly bonded assembly of two crossed lenses, that reduces the distance between the lenses in the beam direction to 30 µm and eliminates the necessity of producing different multilayer systems. Characterization of lens fabrication was performed using a laboratory X-ray microscope. Focusing properties have been investigated using ptychography.