Gate Oxide TDDB Evaluation System for SiC Power Devices under Switching Operation Conditions

This paper proposes a gate-oxide Time-Dependent Dielectric Breakdown (TDDB) evaluation system for SiC power devices under switching operation conditions. A constant voltage High-Temperature Gate Bias (HTGB) test is often used for long-term reliability test of the gate-oxide TDDB of power devices. However, the test condition is different from an actual operation condition. In this paper, a TDDB evaluation circuit that can perform the gate-oxide HTGB test under the operating conditions of the power conversion circuit is described. Using the proposed test circuit, the TDDB evaluation of 1.2 kV Silicon Carbide (SiC) Metal-Oxide-Semiconductor-Field-Effect Transistors (MOSFETs) under switching conditions were performed.