Characteristics of an adaptive floating split gate IGBT
In order to reduce switch loss(ESW)of insulated gate bipolar transistors(IGBT),an IGBT with adaptive floating split gate(AFSG-IGBT)was proposed and investigated by simulation.Based on the traditional carrier-stored trench-gate bipolar transistor(CSTBT),the split gate and P type junction field-effect transistor(JFET)were integrated into the trench gate of this structure.The Miller capacitor(CGC)and ESW can be greatly reduced due to mutual depletion of gate and P type JFET.The channel of P type JFET was pinched off to keep the split gate in a floating state during the conduction of the AFSG-IGBT,thereby a sufficient injection enhancement effect was ensured.Simulation results show that compared with CSTBT,the CGC is reduced by 79.7%and the gate charge(Qg)is reduced by 52.6%at high collector voltage.The turn-on loss(Eon)and turn-off loss(Eoff)of AFSG-IGBT are 37.1%and 28.5%lower than that of CSTBT at the collector current of 100 A/cm2 and the voltage drop(VON)of 1.4 V,respectively.Furthermore,compared with CSTBT,the AFSG-IGBT exhibits a better VON-ESW tradeoff relationship when the driving resistors are 5 Ω and 10 Ω.