A design concept for the low turn-off loss 4.5 kV trench IGBT

In this study, we analyze the turn-off behaviour of high voltage trench insulated gate bipolar transistors (IGBTs) by means of numerical simulation. There are two types of trade-off relationship in the turn-off process. The first relationship is between the voltage-rising process and the tail-current process. This depends on the carrier distribution in the on-state and the MOS channel electron current. The second relationship is between the impact ionization and the MOS channel electron current. In this paper, we propose a new IGBT structure that has the minimum turn-off loss, the optimum carrier distribution in the on-state and the optimum Miller-capacitance.