Abstract Methods of deducing threading dislocation densities (TDDs) from x-ray diffraction (XRD) peak widths have been reevaluated based on crystallography theories. Moreover, Ge/Si heteroepitaxial structures were taken as model materials for investigation. The procedure is tailored in accordance with the specific designs of modern XRD systems to minimize instrumental interference, whereas practical characteristics of heteroepitaxial films are also considered to avoid intrinsic errors. TDDs of samples grown with different epitaxy methods were investigated using the newly implemented XRD method and etch pit density (EPD) method, and satisfactory agreement has been achieved among three independently calculated sets of TDD results: two from XRD and one from EPD. These values were further corroborated by cross-sectional transmission electron microscopy analysis. Key considerations that are of scientific and technical importance in TDD studies are also discussed in detail. The present work provides not only the most up-to-date elucidation on obtaining TDD values in semiconductor epitaxial films, but also insights into the long-existing ambiguity in TDD calculation methods, which will be helpful for the future studies of defect density characterizations in various material systems.
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