Reliability evaluation of SiC MOSFET with performance degradation under multiple conditions based on nonlinear wiener process

A reliability evaluation method for SiC MOSFET components based on the nonlinear Wiener process is proposed using small-sample threshold voltage degradation data under multiple operating conditions. In this method, the exponential function and power function are respectively used to characterize the influences of influencing factor parameters and time effects on the drift coefficient, thereby establishing a mathematical model capable of describing the degradation behavior of SiC MOSFET components. Based on the threshold voltage degradation data of 35 SiC MOSFET component samples, Limited-memory Broyden-Fletcher-Goldfarb-Shanno with Bound constraints (L-BFGS-B) is employed for parameter estimation. Meanwhile, the Bootstrap method is adopted to quantify the uncertainties of the initial degradation amount and influencing factor parameters under small-sample conditions. Through the Monte Carlo simulation method, the reliability evaluation of SiC MOSFET components is conducted under the designed operating conditions, and accurate reliability evaluation results, as well as their confidence intervals are obtained. The results demonstrate that the proposed nonlinear Wiener process model can effectively capture the degradation characteristics of SiC MOSFET components under different operating conditions, providing a scientific basis for further reliability evaluation and life prediction of power electronic equipment.