Improved reliability of a 2200 V SiC MOSFET module with an epoxy-encapsulated insulated metal substrate

Abstract:
The impact of combining epoxy-potting encapsulation with an insulated metal substrate (IMS) on the performance and reliability of SiC MOSFET modules was investigated. Static and dynamic characteristics, thermal resistance, and power cycle tolerance were measured, and a high-temperature bias test and a high-temperature humidity test were carried out. An IMS module with epoxy-potting encapsulation was compared with a conventional ceramic insulated substrate with silicone-gel encapsulation. The IMS module was found to have a higher thermal cycling tolerance, which allowed for a more flexible copper pattern layout. The optimized copper pattern layout enabled reduced conduction loss in the IMS module. In addition, the IMS module exhibited improved power cycling tolerance compared with the conventional ceramic insulated substrate. This improved performance and reliability are expected to contribute to the realization of higher-density power units.