A Damage Path Dependence Mode Identification Method for SiC MOSFETs Due to Power Cycling Test

Power cycling test has been widely used in the packaging reliability assessment of SiC MOSFETs. In real mission profile, stress conditions are time-varying, and it is necessary to use an accumulated damage model for lifetime prediction. However, existing research did not consider the damage path dependence, that is, the influence of historical stress conditions on damage accumulation, resulting in unsatisfactory accuracy in lifetime prediction. This paper proposes a damage path dependence mode identification method based on the trajectory of the defined feature point, and its effectiveness is demonstrated through power cycling test of a kind of SiC MOSFETs. The result indicates that historical stress conditions can affect the damage accumulation of SiC MOSFETs, and in this case, still using the traditional accumulated damage model may lead to severely unreliable prediction results.