Reliability Testing of SiC MOSFETs in Different Power Cycling Operating Modes - Focusing on the Challenges of Body Diode Testing

The qualification of new generations of power electronic devices requires reliability testing, with Power Cycling (PC) being a standard method to evaluate the package related lifetime expectations under application-close conditions. In this paper, a double-trench SiC MOSFET, optimised for low forward conduction losses, is tested in PC forward mode and compared to body diode testing and hybrid mode testing. While forward mode testing followed the expected degradation patterns, body diode and hybrid mode testing in reverse direction showed unusual shifts, particularly affecting the temperature determination. The complications of testing in the reverse direction with an elevated current through the body diode are discussed in more detail.