Raman Characterization of SiGe Nanostructures Formed by Rapid Thermal Annealing

Abstract

This work presents the micro-Raman (µR) analysis in SiGe nanoclusters formed by rapid thermal annealing (RTA). Heterostructure of a-Si:H/Ge/a-Si:H was grown on p-Si (001) substrate by Electron Cyclotron Resonance ECR plasma deposition and e-beam technique. Different parts of the sample were heated at 1000• C during 40, 50, 60 and 70 seconds. The samples as-deposited and RTA processed were characterized by Raman measurements in order to evaluate the Ge concentration and strain for different annealing times. The same parameters were extracted from high-resolution x-ray diffraction (HRXRD) performed in grazing incidence x-ray reflection mode (GIXRR). The µR spectra were sensitive to film strain changes due to the Ge diffusion during RTA process. The association of both characterization techniques provides information about some features of the SiGe nanoclusters at different annealing times. The results show the potential micro-Raman applicability for SiGe nanoclusters embedded in amorphous structure characterization.