Strain, Composition And Crystalline Perfection In Thin Sige Layers Studied By Raman Spectroscopy

摘要

Micro-Raman spectroscopy has been employed for measurements of Ge content and strain-relaxation of thin (< 100nm) Si_(1-x)Ge_x (0.2 < x < 0.35) epitaxial layers grown by molecular beam epitaxy. The phonon line width of both Raman bands, Si-Si, and Si-Ge, was studied in order to determine the crystalline quality of the SiGe layers. The dependence of Si-Si and SiGe line width on Ge content in samples obtained under a variety of growth conditions was also analysed. For the majority of samples studied in this work the phonon line width of both Si-Si and Si-Ge modes increases with decreasing temperature in the very low-temperature regime.