Qualifying a Silicon Carbide Power Module: Reliability Testing Beyond the Standards of Silicon Devices

In this paper, we compare the reliability and robustness requirements of typical silicon carbide applications with a qualification based on silicon standards. We focus on the influence of material properties that need to be considered in terms of reliability when designing module solutions based on silicon carbide. If a qualification is based only on the silicon standards and does not take these properties into account, it can overlook important degradation mechanisms, as outlined in this paper. We present the results of standardized tests like HTRB or HV-H3TRB on the SiC MOSFETs (extended here for our study), discuss power-cycling for SiC MOSFETs and the stressing of devices up to temperatures of 175deg C. Subsequently, we outline two reliability tests focussing on SiC-specific failure mechanisms and their relevance for application, which are not yet part of the standards.