Investigations on the Short-Circuit Degradation and its Mechanism of 1.2-KV 19-A SiC power MOSFETs

To provide a guideline for converter design and fault protection, the failure mechanism and reliability of silicon carbide (SiC) power MOSFETs needs to be further investigated. In this paper, the failure mechanism during short-circuit (SC) of commercial 1.2-KV/19-A SiC power MOSFETs was investigated. After the SC tests, the I
_ds
of the device decreased significantly. Moreover, it was found that the V
_th
and I
_gs
increased obviously. The results demonstrated that negative charges were captured by the gate oxide and accumulated during the SC tests, which is eventually causes degradation of the gate oxide. The results of this study may be useful in the design and application of SiC power MOSFETs.