Substrate temperature and Ge concentration dependence of the microstructure of strained Si-Ge alloys

Abstract

Raman spectroscopy has been employed to investigate the microstructural features of strained Si-Ge layers deposited by the rapid-thermal-process very-low-pressure chemical vapour deposition method. Auger electron spectroscopy was used to determine the Ge concentrations in the Si-Ge layers. The Ge atoms in the high-Ge-concentration Si-Ge alloy are distributed more homogeneously and randomly than in the low-Ge-concentration alloy. The substrate temperature has a great influence on the microstructure of the strained Si-Ge alloy. A high Ge content needs a relatively low substrate temperature to deposit high-quality Si-Ge alloy, but a low Ge content requires a higher growth temperature during the deposition of the Si-Ge alloy.