Evaluation of Crystallinity in 4H–SiC{0001} Epilayers Thermally Etched by Chlorine and Oxygen System

Abstract

A thermal etching with a mixed gas of chlorine and oxygen was applied to analyze the crystal defects in 4H–SiC{0001} epilayers for the first time. The etching rate of the (0001)Si face was more one-tenth slower than that of the (000\\bar)C face. Etch pits and oval hillocks were observed on the (0001)Si and (0001)C faces, respectively. The shapes of the etch pits were similar to those in the case of etching by a molten potassium-hydroxide method. The etch pits on the (0001)Si face were minority carrier traps as confirmed by a planar mapping electron-beam-induced current method. On the other hand, oval hillocks on the etched (0001)C face were not minority carrier traps. On the basis of these results, etching mechanisms are discussed.