Simulation Study of Overcurrent Turn-off Capability in 4500V IGBT

Abstract

According to the requirement of IGBT's over-current turn-off capability, this paper analyzes the factors affecting the dynamic latch-up of IGBT chip during the over-current turn-off process, including the gate width of IGBT cell, the doping concentration of back P + collector and the dVce/dt when the IGBT is turned off. The simulation results show that the anti-dynamic latch-up capability of IGBT can be effectively improved by decreasing the gate width and back P + collector doping concentration. Through multi-cell parallel simulation, it is found that current concentration exists in the process of overcurrent trun-off, which leads to the further increase of the lattice temperature, and the overcurrent turn-off capability declines.