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Electronic or catalytic properties can be modified at the nanoscale level. Engineering efficient and specific nanomaterials requires the ability to study their complex structure–property relationships. Here, Bragg coherent diffraction imaging was used to measure the three‐dimensional shape and strain of platinum nanoparticles with a diameter smaller than 30 nm, i.e. significantly smaller than any previous study. This was made possible by the realization of the Extremely Brilliant Source of ESRF, The European Synchrotron. This work demonstrates the feasibility of imaging the complex structure of very small particles in three dimensions and paves the way towards the observation of realistic catalytic particles. [ABSTRACT FROM AUTHOR]

The observation of atomic ordering and signatures of defects in self-assembled Ge islands using x-ray diffraction techniques have been previously treated as unrelated subjects. However, mutual understanding can be achieved when both subjects are studied in a common frame. Here, we report on measurements and analysis of both defects and atomic ordering in Si1-xGex islands epitaxially grown on Si(001) substrates as a function of growth temperature. By using x-ray diffraction and mapping around a bulk forbidden reflection, defect sizes, and in-plane spacing between nearby dislocations are extracted and related to the composition of the islands. The results fit well with an independent determination using selective wet chemical etching and atomic force microscopy measurements. Moreover, the temperature dependence of the ordered domain size is discussed. Although both atomic ordering and defect formation take place independently in the system, it is found that the relaxation provided by the onset of defects does not affect the formation of ordered domains, recently pointed out to be stabilized by strain and surface equilibrium on islands facets. [ABSTRACT FROM AUTHOR]

Multi‐wavelength (mw) Bragg coherent X‐ray diffraction imaging (BCDI) is demonstrated on a single Au particle. The multi‐wavelength Bragg diffraction patterns are inverted using conventional phase‐retrieval algorithms where the dilation of the effective pixel size of a pixelated 2D detector caused by the variation of the X‐ray beam energy is mitigated by interpolating the raw data. The reconstructed Bragg electron density and phase field are in excellent agreement with the results obtained from conventional rocking scans of the same particle. Voxel sizes of about 63 nm3 are obtained for reconstructions from both approaches. Phase shifts as small as 0.41 rad, which correspond to displacements of 14 pm and translate into strain resolution better than 10−4 in the Au particle, are resolved. The displacement field changes shape during the experiment, which is well reproduced by finite element method simulations considering an inhomogeneous strained carbon layer deposited on the Au particle over the course of the measurements. These experiments thus demonstrate the very high sensitivity of BCDI and mw‐BCDI to strain induced by contaminations. Furthermore, mw‐BCDI offers new opportunities for in situ and operando 3D strain imaging in complex sample environments. [ABSTRACT FROM AUTHOR]

In 3-D integration, dice are vertically interconnected with through silicon via (TSV), which consist of holes etched in a thinned silicon substrate and filled with copper. This process induces thermal strain in surrounding silicon. New trends in 3-D integration imply the fabrication of Si photonic devices like waveguides in silicon-on-insulator (SOI) substrates containing TSVs. Thus, a quantitative analysis of strain in active areas around TSVs is mandatory. In this paper, the strain induced by the TSVs in both the bulk silicon and the SOI layer was investigated by using advanced scanning X-ray nano-diffraction. The crystallographic orientation offset between the separated silicon areas allows decorrelation of the strain in the Si layer of the SOI and Si substrate. Using synchrotron radiation, 2-D quicK continuous mapping of the strain in a region of 50 $ \mu \text{m}\,\, \times $ 50 $ \mu \text{m}$ with 500 nm spatial resolution was performed around a single TSV at room temperature and during in-situ annealing at 460 °C. The strain field induced by the TSV appears negligible in both silicon areas. The effect of in-situ annealing on the strain distribution is surprisingly weak. In the SOI active layer, the strain map mimics the surface pattern generated by the photonic devices processed at high temperature in this thin layer. [ABSTRACT FROM AUTHOR]

Systematic tensile tests were performed on single defect‐free ⟨110⟩ Au nanowires grown by physical vapor deposition while simultaneously recording three‐dimensional Bragg peaks using coherent X‐rays. The trajectory of three‐dimensional Bragg peaks in reciprocal space during tensile testing allowed for measurements of the evolution of strains and rotations of the nanowire, thus sensitively uncovering the full deformation geometry of the nanowire. The transition from elastic to plastic deformation is accompanied by rotations of the nanowire as quantified by analysis of the motion of Bragg peaks, showing the importance of boundary conditions in interpreting nanoscale mechanical deformations. [ABSTRACT FROM AUTHOR]

A reactor cell for in situ studies of individual catalyst nanoparticles or surfaces by nano-focused (coherent) x-ray diffraction has been developed. Catalytic reactions can be studied in flow mode in a pressure range of 10- 2–103 mbar and temperatures up to 900 °C. This instrument bridges the pressure and materials gap at the same time within one experimental setup. It allows us to probe in situ the structure (e.g., shape, size, strain, faceting, composition, and defects) of individual nanoparticles using a nano-focused x-ray beam. Here, the setupwas used to observe strain and facet evolution of individual model Pt catalysts during in situ experiments. It can be used for heating other (non-catalytically active) nanoparticles (e.g., nanowires) in inert or reactive gas atmospheres or vacuum as well. [ABSTRACT FROM AUTHOR]

Semiconductor heteroepitaxy on top of thin compliant layers has been explored as a path to make inorganic electronics mechanically flexible as well as to integrate materials that cannot be grown directly on rigid substrates. Here, we show direct evidences of strain transfer for InAs islands on freestanding Si thin films (7 nm). Synchrotron X-ray diffraction measurements using a beam size of 300 x 700 nm² can directly probe the strain status of the compliant substrate underneath deposited islands. Using a recently developed diffraction mapping technique, three-dimensional reciprocal space maps were reconstructed around the Si (004) peak for specific illuminated positions of the sample. The strain retrieved was analyzed using continuous elasticity theory via Finite-element simulations. The comparison of experiment and simulations yields the amount of strain from the InAs islands, which is transferred to the compliant Si thin film. [ABSTRACT FROM AUTHOR]

Strain in silicon induced by Through-Silicon Via (TSV) integration is of particular interest in the frame of the integration of active devices in silicon interposer. Nano-focused X-ray beam diffraction experiments were conducted using synchrotron radiation to investigate the thermally induced strain field in silicon around copper filled TSVs. Measurements were performed on thinned samples at room temperature and during in situ annealing at 400°C. In order to correlate the 2D strain maps with finite elements analysis, an analytical model was developed, which takes into account beam absorption in the sample for a given diffraction geometry. The strain field along the [335] direction is found to be in the 10-5 range at room temperature and around 10-4 at 400°C. Simulations support the expected plastification in some regions of the TSV during the annealing step. [ABSTRACT FROM AUTHOR]

This paper presents a study of the spatial distribution of strain and lattice orientation in CMOS fabricated strained Ge microstripes using high resolution x-ray micro-diffraction. The recently developed model-free characterization tool, based on a quick scanning x-ray diffraction microscopy technique can image strain down to levels of 10-5 (δa/a) with a spatial resolution of ~0.5 μm. Strain and lattice tilt are extracted using the strain and orientation calculation software package X-SOCS. The obtained results are compared with the biaxial strain distribution obtained by lattice parameter-sensitive μ-Raman and μ-photoluminescence measurements. The experimental data are interpreted with the help of finite element modeling of the strain relaxation dynamics in the investigated structures. [ABSTRACT FROM AUTHOR]

This paper presents a study of the spatial distribution of strain and lattice orientation in CMOSfabricated strained Ge microstripes using high resolution x-ray micro-diffraction. The recently developed model-free characterization tool, based on a quick scanning x-ray diffraction microscopy technique can image strain down to levels of 10-5 (△a/a) with a spatial resolution of ~0.5 μm. Strain and lattice tilt are extracted using the strain and orientation calculation software package X-SOCS. The obtained results are compared with the biaxial strain distribution obtained by lattice parameter-sensitive i-Raman and i-photoluminescence measurements. The experimental data are interpreted with the help of finite element modeling of the strain relaxation dynamics in the investigated structures. [ABSTRACT FROM AUTHOR]

Compositional atomic ordering is a crucial issue in the epitaxial growth of nanoparticles and thin films. Here, we report on a method based on x-ray diffuse scattering close to basis forbidden Bragg reflections to infer the lateral location, the symmetry, and the thermal stability of ordered domains in GeSi dome-shaped islands on Si(001) after growth and during annealing. We observe that atomic ordering does not disappear after annealing, demonstrating that it is a resilient metastable phenomenon. [ABSTRACT FROM AUTHOR]

Compositional atomic ordering is a crucial issue in the epitaxial growth of nanoparticles and thin films. Here, we report on a method based on x-ray diffuse scattering close to basis forbidden Bragg reflections to infer the lateral location, the symmetry, and the thermal stability of ordered domains in GeSi dome-shaped islands on Si(001) after growth and during annealing. We observe that atomic ordering does not disappear after annealing, demonstrating that it is a resilient metastable phenomenon. [ABSTRACT FROM AUTHOR]

The nucleation and the evolution of dislocations in SiGe/Si(001) films can be controlled and confined along stripes aligned along pits carved in the substrate, leaving micrometric coherent areas free of dislocations. In this work, we have addressed the stability of such metastable areas versus, film thickness, different Ge contents (xGe=10%-30%) and larger pit-pattern periods, revealing the flexibility and effectiveness of this method even for coherent areas of about 64 µm². The thermal stability of such configuration has been finally verified by post-growth annealing treatment, in order to simulate device processing. Finally, µRaman spectroscopy and X-ray nanodiffraction have been used to characterize the periodic strain variations across the pattern. [ABSTRACT FROM AUTHOR]

In-situ synchrotron x-ray observations reveal that the ferroelectric behavior of epitaxial (001) PbTiO3 thin films grown on (110) DyScO3 substrates depends on both film thickness and interfacial electrical properties. A 92-nm-thick film was found to exhibit an a/c domain structure with a ferroelectric Curie temperature similar to that theoretically predicted based on the strain state. In contrast, 6-nm-thick films contained only c-oriented domains, and the ferroelectric behavior was found to depend strongly on the nature of the electrical boundary condition at the buried interface. [ABSTRACT FROM AUTHOR]

Mechanical deformation of a SiGe island epitaxically grown on Si(001) was studied by a specially adapted atomic force microscope and nanofocused X-ray diffraction. The deformation was monitored during in situ mechanical loading by recording three-dimensional reciprocal-space maps around a selected Bragg peak. Scanning the energy of the incident beam instead of rocking the sample allowed the safe and reliable measurement of the reciprocal-space maps without removal of the mechanical load. The crystal truncation rods originating from the island side facets rotate to steeper angles with increasing mechanical load. Simulations of the displacement field and the intensity distribution, based on the finite-element method, reveal that the change in orientation of the side facets of about 25° corresponds to an applied pressure of 2-3 GPa on the island top plane. [ABSTRACT FROM AUTHOR]

Plastic relaxation and formation of defects is a crucial issue in the epitaxial growth of nanoparticles and thin films. Here, we report an in situ non-destructive method based on x-ray diffuse scattering close to forbidden reflections to study the formation of defects during the growth of Ge islands on Si(001). The dependence of in-plane spacing between interfacial dislocations, defect size, and density is analyzed as a function of Ge-deposit. It is found that the introduction of additional defects is preferred to relieve strain during growth. [ABSTRACT FROM AUTHOR]

Composition and strain inhomogeneities strongly affect the optoelectronic properties of InGaN but their origin has been unclear. Here we report real-time x-ray reciprocal space mapping that reveals the development of strain and composition distributions during metal-organic chemical vapor deposition of InxGa1-xN on GaN. Strong, correlated inhomogeneities of the strain state and In fraction x arise during growth in a manner consistent with models for instabilities driven by strain relaxation. [ABSTRACT FROM AUTHOR]

Experiments and numerical simulations based on finite element modeling show that the x-ray intensity scattered by comparatively large nanostructures on a substrate is not simply related to their strain in experiments using either grazing incidence or exit because of multiple scattering effects. However, whatever the nanostructure size, the composition profiles are correctly extracted from grazing incidence multiwavelength anomalous scattering. These effects are illustrated for the structural analysis of Ge dome-shaped islands grown on Si(001). [ABSTRACT FROM AUTHOR]

The growth of Ge on Si(001) is investigated in situ at 500 and 600 °C, combining grazing incidence diffraction, multiple wavelength anomalous diffraction, and small angle scattering. This allows probing simultaneously the island shape, strain state, composition, and the transition from wetting layer to island growth. At 500 °C no intermixing occurs. The wetting layer is found to decrease by one atomic layer at the onset of island nucleation. At 600 °C interdiffusion plays an important role in strain relaxation leading to a more stable wetting layer. Small angle scattering yields the island morphology and shows the transition from pyramids to multifacetted domes. [ABSTRACT FROM AUTHOR]