Comparison of Gate Oxide Lifetime Predictions with Charge-to-Breakdown Approach and Constant-Voltage TDDB on SiC Power MOSFET

Abstract

The gate oxide reliability for commercial silicon carbide (SiC) power metal-oxide-semiconductor field-effect-transistors (MOSFETs) is significant for their applications. The constant-voltage time-dependent dielectric breakdown (TDDB) measurement is commonly utilized to evaluate the dielectric failure time of the SiC power MOSFETs under normal operation. A charge-to-breakdown approach based on the oxide tunneling current behavior has been proposed recently for the projection of dielectric failure time. The method is less time-consuming but requires the oxide leakage current behavior of the devices to follow a universal envelope. This work compares the predicted failure times of commercial 1.2 kVSiC MOSFETs from the charge-to-breakdown approach and the constant-voltage TDDB method. The results show that the constant-voltage TDDB method applied under low oxide fields ($\text{E}_{\text{o}\text{x}}$ <9MV/cm) produce the most conservative prediction of the device lifetime.