Switching Stability Analysis of Paralleled RC-IGBTs With Snapback Effect

In this article, a study of the snapback behavior of reverse conducting IGBTs (RC-IGBTs) by means of 2-D TCAD simulations is carried out. Half-cell TCAD models of 1200-V RC-IGBT structures with different snapback voltage levels were generated by varying the peak doping concentration of the punch-through N-buffer region. First observations show that snapback could be an issue for low current switching commutations of paralleled RC-IGBTs operating at low temperatures, where one device falls back into unipolar mode and current is completely misshared. Results show that the RC-IGBT snapback voltage level, circuit variations, and operating conditions play a critical role for determining whether the parallel RC-IGBTs operate in a stable or unstable mode.