SiC MOSFET body diode reverse recovery

The turn-off transient of SiC MOSFET body diodes differs from that of Si pn-diodes in IGBT circuits due to their unique characteristics. The output capacitance has a larger, and the bipolar charge a smaller impact. However, this changes at elevated temperatures and high current densities.

Moreover, in fast switching applications, the commutation loop stray inductance plays a significant role. The conventional definition to determine Erec and Qrr may give misleading results that do not represent the actual device properties. This talk discusses the unique characteristics and various influences on the body diode turn-off behavior. This whitepaper explains:

• The unique characteristics of SiC MOSFET body diodes,

• how body diode turn-off is influenced in fast switching applications,

• why the conventional definition to calculate Qrr and Erec may give largely misleading results,

• what comprises reverse recovery losses of SiC MOSFETs, and

• how the user can optimize the turn-off behavior in his application.

First publication of the paper at PCIM Europe Digital Days 2021.