Properties of Thermally Etched 4H-SiC by Chlorine-Oxygen System

Abstract

By the use of Cl2-O2 thermal etching method, the etching rates of 4H-SiC were reached to about 1μm/h for Si and 40μm/h for C face at 950oC. Etch pits only appeared over 0.25-μm-etched depth on the 4H-SiC (0001) Si face. The shapes and density of etch pits are similar tendencies in the case of molten KOH etched surface. To study the relationship between thermally etched surface features and crystal defects, the planar mapping electron-beam-induced current (EBIC) technique was carried out. Almost dark areas in the EBIC image correspond to the etch pits. From the EBIC image, a shell-like pit formed by the Cl2-O2 etching on the (0001) Si face is a basal plane dislocation.