Abstract
The reduction in temperature-dependent hole concentration p(T) in Al-implanted p-type 6H-SiC by 1 MeV electron irradiation is investigated. By analysis of p(T), the density (NA), level position (EA) in the bandgap and nature of the acceptor are determined, and this acceptor is assigned to an Al acceptor. EA is independent of irradiation fluence (Φ), while NA is strongly dependent on Φ. We derived an analytical expression for the fluence dependence of NA and we estimated the removal coefficient (i.e., removal cross-section) of NA to be 6.4×10-18 cm2 for 1 MeV electron irradiation. The reduction in p(T) by electron irradiation is found to be mainly due to the decrease in NA, not to the increase in the density of deep-level defects in the bandgap, because the decrement in NA is much larger than the increment in the density of deep-level defects.