A Multiepi Superjunction MOSFET With a Lightly Doped MOS-Channel Diode for Improving Reverse Recovery

A multiepi (ME) superjunction (SJ) MOSFET with a lightly-doped MOS-channel diode (MCD) is studied by TCAD simulations. When the p-pillar is formed by the ME process, the resistance of the p-pillar can be much higher than that of a uniformly doped p-pillar, which helps to suppress reverse recovery oscillations of the body diode. Besides, by introducing the lightly doped MCD, electrons can easily flow from the n-pillar into the source contact when the body diode is in the ON-state. Thus, the hole injection efficiency of the body diode can be lowered to reduce reverse recovery charge ( Q _rr ) and further suppress reverse recovery oscillations. Simulation results show that the proposed SJ MOSFET is able to obtain a 64% lower Q _rr and much lower reverse recovery oscillations than the conventional SJ MOSFET with a uniformly doped p-pillar.