SiC MPS Diodes – Impacts of Package Inductance and Charge Carriers on Dynamic Switching Behavior

Abstract:
This study investigates the reverse recovery behavior of Silicon Carbide (SiC) Merged-PiN-Schottky (MPS) diodes, analyzing the effects of case temperature, switching speed and turn-off currents. The diodes share the same die technology but differ in current ratings and package types. Measurements assess both the influence of packaging on switching behavior and the impact of internal charge carrier dynamics at different operating points. The results show that the bipolar charge contribution to the reverse recovery charge increases significantly with higher currents and temperatures, leading to more pronounced switching effects. However, up to a certain turn-off current, unipolar charge remains dominant, even at high temperatures, resulting in minimal impact on switching behavior. Package inductance, originating from lead and bond-wire contributions, affects voltage overshoot and oscillations at the die within the package but causes only minor differences in switching characteristics between the investigated packages when the printed circuit board (PCB) remains unchanged.