Comprehensive Analysis of Electrical Parameters Degradations for SiC Power MOSFETs Under Repetitive Short-Circuit Stress

Abstract

The degradations of electrical parameters for silicon carbide power MOSFETs under repetitive short-circuit (SC) stress are investigated in detail in this paper. It demonstrates that the generation of negative charges along the gate–oxide interface of the channel region is the dominant degradation mechanism, which results in the increase in the threshold voltage ( ${V}_{\text {th}}$ ) and the rise of ON-state resistance ( ${R}_{\text {dson}}$ ) under low gate voltage bias condition. Furthermore, degradations of dynamic characteristics including gate charge ( ${Q}_{\text {g}}$ ) and switching behaviors of the device after the repetitive SC stress are extracted and analyzed for the first time. It illustrates that the increased ${V}_{\text {th}}$ contributes to the rise of the Miller plateau voltage ( ${V}_{\text {gp}}$ ), which further leads to the increase in gate–source charge ( ${Q}_{\text {gs}}$ ). Meanwhile, the increase in the turn-ON time and the reduction of turn-OFF time are observed, which are also resulted from the positive shifts of ${V}_{\text {th}}$ and ${V}_{\text {gp}}$ , leading to the rise of turn-ON switching energy ( ${E}_{{ \text {on}}}$ ) and the decline of turn-OFF switching energy ( ${E}_{\text {off}}$ ), respectively.