Experimental Investigation on Avalanche Robustness of SiC MOSFETs in the Aging Process

In this paper, the long-term avalanche energy withstanding ability of commercial 1.7-kV 4H-SiC MOSFETs in the process of bipolar degradation is systematically evaluated and analyzed. The test benches are constructed for bipolar degradation tests and unclamped inductive switching (UIS) tests. The experimental results show that the on-resistance of devices appears significant increment with the increasing stress time. Tacking the increment of on resistance as the indicator, the SiC MOSFETs are divided into three aging degrees, and the avalanche withstand energy decreases gradually with the aging of the devices. Moreover, the safe avalanche operation area (SOA) is established in the aging process.