Oxide Breakdown Reliability of SiC MOSFET

The gate oxide of SiC MOSFET has been confirmed to exhibit enough intrinsic lifetime at high temperatures. The real problem of gate oxide in SiC MOSFET is nevertheless the abundant extrinsic defects which may result in early failures and need to be addressed. A “Lucky Defect Model” was proposed to explain the early failures of gate oxide in SiC MOSFET, arguing that enhanced trap-assisted tunneling current led by the point defects grown into the gate oxide of SiC MOSFET, instead of the conventional contamination induced local-thinning theory, is the origin of observed extrinsic failures. However, in this paper, we will provide evidences showing that local-thinning, or more precisely, locally enhanced electric field, can still be an important contributor to the extrinsic failures and requires continuous improvement.