Impact of Kelvin Source Connection (KSC) vs. Common Source Connection (CSC) on Power Cycling Aging Characteristics of Silicon Carbide (SiC) MOSFETs

This study investigates the reliability of Silicon Carbide (SiC) MOSFETs under high-temperature power cycling, focusing on the degradation mechanisms induced by Kelvin Source Connection (KSC) and Common Source Connection (CSC) configurations. Experiments were conducted on commercial 1200V/30A devices through 28,000 power cycles under junction temperatures of 175-220°C and load currents of 18-20A. Results demonstrate that under high-temperature (220°C) and high-current (20A) stress, KSC devices exhibit significantly greater threshold voltage drift (15% for DUT2) compared to CSC devices (~10% for DUT3-4). Notably, KSC devices show a 20% abrupt increase in on-resistance after 27,000 cycles, while CSC devices display earlier but milder packaging degradation. The work reveals the accelerated gate oxide degradation in KSC structures caused by insufficient drive-power loop decoupling, and highlights CSC's reliability advantages through optimized bond wire stress distribution. This study provides theoretical guidance for high-reliability SiC device packaging design and holds substantial engineering significance for SiC MOSFET durability in high-temperature power applications such as electric vehicles and photovoltaic inverters.