Measurement of strain components for 4H-SiC by using Raman microspectroscopy.

Abstract

Recently, SiC power devices are expected to replace conventional Si devices. In the semiconductor field, the local stresses and strains affecting these device performance and reliability are very important. In this study, stress/strain measurements of 4H-SiC was carried out by Raman microspectroscopy with submicron spatial resolution. First, the Raman scattering intensity of the A₁ and E₂ vibration modes in single crystal SiC was theoretically obtained. These results for each vibration mode were good agreement with those obtained from the polarization intensity measurements in single crystal SiC, the polarization condition to decompose the double degeneracy of SiC were determined. Next, the relations between the change in Raman shift and the strain components were theoretically derived based on the energy change under the mechanical loading. These equations include three unknown parameters. The three potential parameters included in these equations were determined from the relationships between Raman shift and strain by various loading test, and then the possibility of measurement of stress/strain components in SiC devices were clarified.