Testing of SiC MOSFETs for short over-current pulses of 1 ms

Over-currents (OCs) in the power system could be caused by fluctuations in the load, bus voltage, etc. In this article, TO-247 MOSFETs have been stressed for over-currents with a pulse duration of approximately 1 ms for two times OCs (2 OCs) to five times OCs (5 OCs). The junction temperature has been estimated and the failure modes are discussed. It has been observed that the devices do not show degraded behavior (change in on-state resistance and threshold voltage) for 100 cycles until 4.5 OCs. The devices failed anywhere between the first cycle to seven cycles for 4.8 OC and the devices always failed in the first cycle for 5 OCs. This observation gives an estimation of the limit of stressing the devices for short pulses of a few milliseconds.