Impact of Elevated Humidity Conditions on the Thermal and Mechanical Reliability of Silicon Carbide MOSFETs

Silicon carbide metal oxide semiconductor field effect transistors(SiC MOSFETs)are widely used in new energy vehicles, photovoltaic systems, and other outdoor working conditions, and their long-term operational reliability is affected by factors such as ambient temperature and humidity. High humidity environments will cause degradation of SiC MOSFET packages, but the associated aging mechanism is unclear. Thus, to better understand these effects, this work simulates environmental stresses using two testing setups: a high voltage-high humidity high temperature reverse bias (HV-H3TRB) test platform and a power cycling test (PCT) platform. Test results show that moisture causes corrosion at the bonding wire and solder interface, which leads to an increase in overall device thermal resistance and a reduction in bonding wire connection. The combination of these two conditions resulted in a 32% reduction of the power cycling lifetime, guiding the reliability evaluations of power devices in outdoor applications.