Carbon Vacancy Engineering on High-Temperature Annealing as a Cost-Effective Approach for Reverse Recovery Suppression in SiC-MOSFETs

A body diode is commonly employed as a free-wheeling diode to reduce costs of SiC components instead of an external Schottky barrier diode. However, one of the key issues is higher reverse recovery loss due to bipolar charge contribution to reverse recovery charge. In this study, we investigated the impact of high-temperature annealing on the characteristics of MOSFETs as a cost-effective approach to introduce minority carrier lifetime killers. The trap densities of Z 1/2 center and EH 6/7 center can be controlled by activation annealing temperature. Q rr of 1900°C measured at 150°C was significantly decrease by 67% compared to that of 1750°C attributed to the 89% suppression of Q BIP . However, reverse leakage current increased adversely with the activation annealing temperature. R on and V th increased with the activation annealing temperature. The trade-off of the annealing temperature worsened slightly compared to that of the doping concentration. It is still possible that high-temperature annealing represents a cost-effective approach to improve the reverse recovery characteristics of the body diode.