Thesis March 04, 2020

Abstract:
Nanotechnologies rely on the introduction of strain engineering to enhance semiconductor devices performances. As a consequence, non-invasive characterization methods with high spatial resolution and strain sensitivity on low-amount-of-matter samples are required. This PhD work focuses on methodology of X-ray diffraction techniques performed in the Bragg geometry, which allows probing the structural properties of crystalline samples. Firstly, the Scanning X-ray Diffraction Microscopy technique, developed on a fast-timescale at the ESRF ID01 undulator beamline, is described through a thorough analysis of an experiment performed on ultra-thin strained SiGe-on-insulator patterns. Secondly, this manuscript focuses on two coherent diffraction imaging techniques, namely Bragg CDI, which yields complex density and strain map of nano-meso crystalline objects, and Ptychography, which use translational diversity to produce quantitative maps of complex transmission function of non-crystalline objects. The motivation developed in this PhD work is to combine these two techniques that both promote highly sensitive phase-contrast properties, in order to provide ultra-high resolution on complex/extended samples. Bragg Ptychography is thus introduced, along with algorithmic descriptions and considerations on the X-ray beam characterization, the latter being still a key component for successful reconstructions.

Keywords:
Nanostructures, coherent diffraction imaging, X-rays, Synchrotron Radiation