Application of Raman Scattering to Study the Strain Distribution in SiGe Layers

TL;DR

This paper introduces a nondestructive Raman scattering method to analyze strain and composition distribution in SiGe alloy films, utilizing multiple laser lines for depth profiling.

Contribution

It presents a new simple and efficient Raman technique capable of simultaneously measuring Ge composition and strain in SiGe layers.

Findings

Ge fractional composition x is about 0.50.

Strain decreases from the interface to the surface.

Method is effective for depth-resolved analysis.

Abstract

In this paper, we mainly present a new simple, efficient and nondestructive Raman scattering analysis method to study the distribution of strain in SiGe alloy films. The method can simultaneously determine both Ge fractional composition x and strain of SiGe films. We use the Ar+ laser lines (514.5, 488 and 457.9 nm) to detect the information of different depth of SiGe layers. The results show that the x value (about 0.50) of Si1-xGex and the strain of the films decrease from the interface between SiGe layers and Si substrates to SiGe surface.