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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> ) and the rise of ON-state resistance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dson</sub> ) under low gate voltage bias condition. Furthermore, degradations of dynamic characteristics including gate charge (Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> ) 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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> contributes to the rise of the Miller plateau voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gp</sub> ), which further leads to the increase in gate-source charge (Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> ). 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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> and V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gp</sub> , leading to the rise of turn-ON switching energy (E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> ) and the decline of turn-OFF switching energy (E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ), respectively.