A Novel Low Turn-Off Loss and Snapback-Free Reverse-Conducting SOI-LIGBT With Integrated Polysilicon Diodes

A novel reverse-conducting (RC) lateral insulated gate bipolar transistor based on the silicon-oninsulator (SOI-LIGBT) with integrated parallel/antiparallel polysilicon diodes (DF and DR) on the top of the anode active region is proposed and investigated by simulation. During the turn-off transient, the major part of the excess electron current flows through the parallel diode DF which achieves a low turn-off loss (EOFF). While during the forward-conducting state, the voltage across the p+anode/n-buffer junction can rapidly increase to the junction's built-in potential (Vbi) at low anode current, which results in snapback immunity. Moreover, the antiparallel diode DR enables the proposed device to realize RC capability. Simulation results reveal that the proposed RC-LIGBT can realize superior EOFF-VON tradeoff relationshipthan both the conventional LIGBT and the separated shorted-anode LIGBT (SSA-LIGBT). When EOFF is 0.44 mJ/cm
²
, VON of the proposed RC-LIGBT is 1.95 V, which is 0.47 V lower than that of the SSA-LIGBT. Under VON of 1.95 V, EOFF of the proposed RC-LIGBT is 0.44 mJ/cm
²
, which is reduced by 44.3% than that of the conventional LIGBT. Furthermore, the reverse recovery charge (Qrr) of the proposed device is reduced by 25.8% compared with that of the conventional one. In addition, diodes DF and DR and the thin oxide layer below can be fabricated during the implementation of the polysilicon gate. Therefore, there is no extra difficulty in the fabrication process of the proposed RC-LIGBT.