Failure Mechanism and Simulation of Gate Wrong Turn-on for IGBT in the Off State

Abstract

When IGBT in the off state is subjected to certain voltage changes, internal junction capacitor charging will generate displacement current, which will cause gate voltage to rise and even exceed threshold voltage value, leading to wrong turn-on of IGBT. In serious cases, it will cause short circuit and cause device failure. Based on the existing Hefner model of IGBT, the failure mechanism of IGBT is studied and the formula is deduced from semiconductor physics. the expression of displacement current is obtained, and the displacement current caused by the change of capacitance itself is added. Finally, the correctness of the analysis is verified by simulation.