Turn-on analysis of silicon insulated gate bipolar transistors with emitter trenches

Abstract

In this study, we analyzed the turn-on of silicon insulated gate bipolar transistors (IGBTs) with an emitter trench. The tail of collector-to-emitter voltage during turn-on fluctuated when an emitter trench was inserted. Interestingly, the gate-to-collector capacitance of IGBTs with an emitter trench was lower than that without an emitter trench. The internal hole current distribution at the time of the tail of collector-to-emitter voltage was investigated by device simulation. The hole current was diverted, passing adjacent to the emitter trench. It was clarified that the fluctuation in the tail of collector-to-emitter voltage originates from a decrease in PNP transistor gain associated with this change of the hole current path. We demonstrated that this fluctuation in the tail of collector-to-emitter voltage can be suppressed by connecting the emitter trench to a gate electrode.