Control of carbon vacancy in SiC toward ultrahigh-voltage power devices

A carbon vacancy defect is one of the most abundant point defects in SiC (as-grown, irradiated, annealed) and of technological importance because the acceptor-like level of a carbon monovacancy (Z1/2 center: EC - 0.63 eV) works as the primary carrier-lifetime killer in 4H-SiC. The carbon vacancy defects can be preferentially generated by either low-energy electron irradiation or high-temperature treatment in an inert gas ambient. On the other hand, the carbon vacancy defects can be almost eliminated by either a carbon-ion implantation process or thermal oxidation. By combination of these techniques, the density of carbon vacancy defects can be controlled in the wide range from 1011 cm−3 to 1015 cm−3 or even higher.