Short-circuit performance of multi-chip SiC MOSFET modules

摘要

This paper presents short-circuit test results on commercial, multi-chip 1200 V SiC MOSFET half-bridge modules up to 860 V dc, suitable for three-phase 480 V grid-interfaced applications. The peak short-circuit current is measured to be over 5 kA, with around 3 μs withstand for the given voltage and commutation loop inductance. During the post-failure investigation, it is observed that only a few chips have failed in some cases, leading to a hypothesis that an asymmetric stress distribution is initiating the devices' failure. As the chiplevel data are not available for the high current modules, this problem is investigated by testing parallel connected TO-247 discrete devices from the same device manufacturer, after characterizing the individual devices. The gate threshold characterization data and the test results on the parallel connected discrete devices explaining the failure mechanism are provided. It is to be noted that the devices are intentionally subjected to destructive tests, with the objective of evaluating their failure mechanism.