Cause Analysis on the Abnormal Failure of SiC Power Modules During the HV-H³TRB Tests

The SiC die has broad application prospects in new energy vehicles due to its excellent performances. In recent years, with the continuous development, the safety and reliability of SiC power modules have become particularly important and highly valued. In this paper, a case about the abnormal failure of SiC power modules during the High Voltage-High Humidity High Temperature Reverse Bias (HV-H3TRB) tests was addressed. According to the failure phenomena, a systematical investigation was conducted to explore the root cause by a series of methods such as failure point localization, synchrotron radiation infrared spectrum (SR-IR), time of flight-secondary ion mass spectrometry (TOF-SIMS), the ion beam method, scanning electron microscope (SEM) equipped with the energy dispersive spectrometer (EDS). Finally, the root cause of the failure was determined through comprehensive analysis, and based on the conclusions, some corresponding countermeasures were also proposed. Hopefully, the achievements obtained in this paper would be of great significance for improving the reliability of SiC power modules and avoiding similar failure in future manufacturing process.