Minority Carrier Transient Spectroscopy of As-Grown, Electron Irradiated and Thermally Oxidized p-Type 4H-SiC

Abstract

A total of nine electrically active levels have been detected in as-grown and electron irradiated p-type 4H-SiC epilayers. These traps are found in the 0.32-2.26 eV energy range, above the valence band edge (EV). Of these, six are majority carrier traps whereas three are minority carrier traps. We found that thermal oxidation affects the concentrations of two midgap levels, the majority carrier trap, labeled HK4 and the minority carrier trap identified as EH6/7. The analysis of the irradiation energy and dose dependence of the concentration of these two traps, rules out the possibility that they may share the same origin.