Polarized Raman Scattering in Silicon Layers on Sapphire

Abstract

The intensities of polarized components of Raman light scattering are measured for different crystallographic directions in epitaxial layers of silicon on sapphire. The experiment shows that the scattered radiation has a strong depolarized component, which is directly related to the occurrence of defects in the epitaxial layer. A model of an ensemble of crystallites is proposed to describe a defect crystal silicon layer on sapphire. It is shown that the characteristic value of disordering of crystalline domains in the epitaxial layer can be determined from the ratio between the intensities of the polarized and depolarized components. From measurements of the Raman scattering intensity as a function of the crystallographic direction, the anisotropy of the Raman scattering tensor is determined. Numerical values for two samples are obtained.