Reduction in Al Acceptor Density by Electron Irradiation in Al-Doped 4H-SiC

Abstract

The influence of electron irradiation on the hole concentration in Al-doped 4H-SiC epilayers is investigated with free carrier concentration spectroscopy (FCCS) using the temperature dependent hole concentration . By 4.6-MeV electron irradiation, is reduced over the whole temperature range. Using FCCS, the densities and energy levels of acceptors or hole traps are determined. In the unirradiated and irradiated samples, ~200 meV and ~370 meV acceptor levels or hole-trap levels are detected. By irradiation, only the density of Al acceptors whose energy level is ~200 meV is reduced from 6.2×10 ) (T p ) (T p