Statistical Electrothermal Simulation for Lifetime Prediction of Parallel SiC MOSFETs and Modules

Abstract

In this paper, a temperature-dependent SPICE model of SiC power MOSFET is used for statistical electrothermal (ET) simulations of parallel devices for multichip power module applications. The proposed approach is applied to a power module in a half-bridge configuration, where parallel MOSFETs are subject to mismatched parameters. The impact of threshold voltage and current factor statistical fluctuations on energy dissipation during hard switching conditions is evaluated by means of Monte Carlo ET simulations. Thereafter, the mean time-to-failure (MTTF) has been estimated by using the lifetime models from literature for SiC chip. Finally, the effect of current imbalance on the acceleration factor due to changes in devices self-heating is analyzed and discussed.