Improvement Design for Turn-On Switching Characteristics in Surface Buffer Insulated Gate Bipolar Transistor

A design direction in surface buffer insulated gate bipolar transistor (SB-IGBT) is shown for improvement of turn-on switching characteristics, such as switching controllability,current surge and turn-on loss. At turn-on switching, hole current around the gate degrades the switching controllability and induces EMI noise due to negative gate capacitance. However, SB-IGBT can be designed to suppress the negative gate capacitance by enhancement of hole evacuation through pMOS channel. Although turn-on loss can be decreased by small gate-collector capacitance Cgc, the influence of negative gate capacitance is remarkable. Therefore, TCAD simulation results show that high hole evacuation through pMOS channel and optimum C
_gc
design are effective to improve turn-on switching characteristics.