Power Cycling Test Failure Analysis of SiC MOSFET Devices

In this paper, we performed power cycling test (PCT) under harsh operation conditions: mean junction temperature (Tjm) of 120 ℃ and junction temperature swing (ΔTj) of 110 ℃, to analyze failure modes in PCT for commercial silicon carbide (SiC) MOSFETs with TO-247 package. To attain this goal, various electrical characteristics, including output curve, transfer curve, and capacitances, were measured before and after the PCT and were compared. In addition, the scanning electron microscope (SEM) inspection, the secondary ion mass spectrometry (SIMS) analysis, and the numerical simulation were utilized. The failure mode analysis reveals that the cracks in the source wire bond created after PCT increased the on-state resistance and that the SiO2/SiC interface degradation also leads to higher on-state resistance (RDS,on).