Gate Leakage Current and Time-Dependent Dielectric Breakdown Measurements of Commercial 1.2 kV 4H-SiC Power MOSFETs

Gate leakage current and constant-voltage time-dependent dielectric breakdown (TDDB) measurements at room temperature and elevated temperatures of commercially available large-area 1.2 kV 4H-SiC power MOSFETs are performed to investigate their gate oxide reliability and better understand their failure modes. It is shown that Fowler-Nordheim (F-N) tunneling current is the dominant mechanism contributing to the gate leakage current. Despite anomalous gate leakage current behaviors that could be caused by interface states densities (D-it) and near interface oxide traps, leakage currents at normal operating condition (V-G = 20 V at 28 degrees C) are less than 100 pA for all vendors. Extrapolation from TDDB measurements shows that the predicted lifetimes when V-G = 20 V at both 28 degrees C and 175 degrees C are far longer than the targeted 10 years.