On the Intrinsic and Extrinsic Reliability Challenges of SiC MOSFETs

This paper provides a status overview of both intrinsic and extrinsic gate oxide reliability on SiC MOSFETs. Forward gate bias TDDB data is used to extract the time-to-fail of the intrinsic population. In addition, from the Ig-t characteristics during TDDB stress, a “safe-operation area” can be extracted. Similarly, device lifetime under reverse bias stress (“accelerated reverse bias”) is determined and compared to the FIT rate under Cosmic Ray Irradiation. Finally, the extrinsic failures of SiC MOSFET is addressed. The field acceleration factor for extrinsic failure is found to be lower than for intrinsic failure. The statistical treatment for field return rate extraction is outlined.