This paper presents a practical condition monitoring method for detecting bond wire degradation in TO247 packaged SiC MOSFET devices using ON-state resistance (RdsON) compensated for junction temperature variations. While RdsON is a promising health indicator, its strong dependence on junction temperature (Tj) limits its direct applicability in realworld systems. To overcome this, a novel approach is proposed that uses the temperature measured at the drain leg (TMidleg) as a proxy for Tj, enabling temperature-compensated RdsON measurements during power cycling tests (PCT). The method is experimentally validated on two SCT30N120 SiC MOSFET devices under active power cycling test conditions. The results demonstrate a clear correlation between the increase in RdsON measured at the defined TMidLeg and bond wire degradation, with similar trends observed when RdsON is evaluated at the minimum junction temperature (Tj,min) estimated using the TSEP method. Failure analysis confirms bond wire cracking without significant solder layer delamination, demonstrating the effectiveness of the proposed method for bond wire-related failure detection.
Part of ISBN 9798331541309
QC 20260317