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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]

A procedure to retrieve the three-dimensional strain and composition fields of single-crystalline nanoparticles using a combination of anomalous and coherent x-ray diffraction was developed. The applicability of the method was demonstrated using numerically generated data for AgIAu core-shell nanowires for which the epitaxy-induced strain field was simulated by the use of the finite element method for infinitely long nanowires with either abrupt ("as-prepared") or diffuse ("as-annealed") interfaces between core and shell. First, the influence of the elemental distribution and the associated inhomogeneous strains on the x-ray diffraction patterns were described. Next, the diffraction patterns as determined for different x-ray energies were inverted by applying phase retheval algorithms. Only if diffraction patterns at different energies are available and inverted can the concentrations and displacements be obtained subject to specific assumptions. [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]

The strain distribution induced by TSVs is extensively studied in silicon by using submicron resolution synchrotron X-ray diffraction techniques. Simulations with finite elements are performed to interpret the experimental strain results. Stress and strain in silicon are found to be small at room temperature (< 7 × 10 − 5 ), while measurements and simulations at annealing temperature (400 °C) show a reverse sign of strain and support a plastic behavior of copper in some regions of the TSV. [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]