Low turnoff loss reverse-conducting IGBT with double n-p-n electron extraction paths

A low turnoff loss snapback-free reverse-conducting insulated-gate bipolar transistor (RC-IGBT) with a novel collector structure is demonstrated. The n-collector is partially enclosed by a floating p-layer (p-float) which acts as a barrier for electrons at low current in the forward conduction state and contributes to the snapback-free forward conduction characteristics. The p-float makes the proposed device feature double n-p-n electron extraction paths, the n-drift/p- float/n-collector (n-p-nl, n-drift is emitter) and the n-buffer/p-float/ n-collector (n-p-n2, n-buffer is emitter), both of which can be activated during turnoff. As numerical simulations show, the two n-p-n extraction paths, especially n-p-n2 which is more effective than n-p-nl, are favourable to the ultra-low turnoff loss.