A Novel Super-junction MOSFET with Enhanced Switching Performance and Ruggedness

Abstract

In this paper, a novel super-junction (SJ) MOSFET with enhanced switching performance and ruggedness is proposed and investigated by the method of TCAD simulations. An N+/P- polysilicon junction gate electrode and separation layer between P-base and P-pillar are introduced to the trench SJ-MOSFET. For the N+/P- junction trench gate, the P- polysilicon located in the bottom of the trench plays the role of insulating layer, which efficiently reduces the gate charge (QG), thus increasing the switching speed and reducing the switching loss. The P-pillar does not contact with P-base so a depletion region is formed and the gate to drain charge (QGD) is reduced. Besides, the specific separation layer also inhibits the activation of the parasitic bipolar transistor (BJT) to improve the unclamped inductive switching (UIS) capability. The results of the simulation reveal that the proposed SJ-MOSFET is better in switching performance and ruggedness.