Investigation of Time-Dependent Dielectric Breakdown on Commercial SiC MOSFETs Using Constant-Voltage and Pulse-Voltage

This study estimates the intrinsic gate oxide lifetime of two generations of commercial planar SiC MOSFETs using pulse-voltage time-dependent dielectric breakdown (PV-TDDB) and constant-voltage (CV) time-dependent dielectric breakdown (TDDB) at $150~^{\circ }$ C. Compared to the conventional CV time-dependent-dielectric-breakdown (CV-TDDB) method, the proposed PV-TDDB method yields significantly higher predicted lifetimes at the same oxide electric field, with estimated lifetimes closer to actual operational lifetimes. Furthermore, the gate leakage current behaviors under both conditions are analyzed. The effects of charge trapping in the gate oxide on the gate leakage current and the lifetime are examined, along with the effects of the high-frequency gate voltage pulses on the gate oxide and trapped charges. Finally, the gate oxide lifetime of the two generations of devices is compared. The proposed PV-TDDB method enhances conventional CV-TDDB testing by incorporating pulsed gate oxide voltages, thereby providing a more representative assessment of oxide lifetime under real operating conditions.