A Snapback-Free and Low-Loss RC-IGBT With Lateral FWD Integrated in the Terminal Region

Abstract

A novel Reverse Conduction Insulated Gate Bipolar Transistor (RC-IGBT) with Lateral Free-Wheeling Diode (FWD) integrated in the Termination is proposed and investigated by simulation, named LDT-RC-IGBT. Firstly, the Equi-Potential Ring (EPR) of the termination acts as an anode and the N-Stopper/N-Collector of the termination acts as the cathode of the anti-parallel built-in diode. The N-Stopper/N-Collector is shorted to the P-Collector, and it also acts as the electric filed stopper in the breakdown state. Secondly, the N-Collector and the P-Collector are designed apart at the surface and bottom, respectively. Thus the short effect of the N-Collector of the conventional RC-IGBT is avoided, and the snapback is completely eliminated. Thirdly, the P-Collector is not replaced by the N-Collector so that the hole injection is much higher than the conventional RC-IGBT, thus the forward voltage drop (Von) can be reduced remarkably, which is favorable to the decrease of conducting energy loss. The results show that, the LDT-RC-IGBT not only eliminates the snapback but also reduces Von, it achieves a better trade-off between Von and turn-off loss Eoff. At the same Von of 1.27 V, the Eoff of LDT-RC-IGBT is 2.06 mJ/cm2, which is 35.2%, 45.2% and 46.3% lower than that of the conventional RC-IGBT(3.19 mJ/cm2), TPRC-IGBT(3.78 mJ/cm2) and DARC-IGBT(3.85 mJ/cm2), respectively. At the same Eoff of 3.10 mJ/cm2, the Von of LDT-RC-IGBT is 1.17 V, which is 10% and 15.8% lower than that of the conventional RC-IGBT(1.30 V) and the DARC-IGBT(1.39 V), respectively.

Keywords

• RC-IGBT
• breakdown voltage
• turn-off
• snapback