Reverse-conducting insulated gate bipolar transistor with an anti-parallel thyristor

An IGBT with a novel reverse conduction structure is presented and first demonstrated by numerical simulations. As opposed to the standard anti-parallel diode existent in power MOSFETs and conventional reverse conducting IGBTs, here we propose an anti-parallel reverse-conducting thyristor with a very low break-over voltage. The structure includes a narrow-base npn BJT to realise an embedded thyristor which acts like a diode in its on-state conduction. In addition, the narrow-base npn BJT helps to mitigate the snapback issue which usually appears in the conventional RC-IGBTs. The new device also feature a number of floating N+ dots in the N-buffer layer to adjust the device static and switching performance without the need of cumbersome lifetime killing processes. Simulation results have shown that the new device can achieve a low on-state voltage of 1.3 V in forward conduction and 1.2 V in reverse conduction, for 600-V blocking rating, coupled with fast switching performance.