A Snapback-Free Reverse Conducting Insulated-Gate Bipolar Transistor With Discontinuous Field-Stop Layer

In this paper, a novel reverse conducting insulator gate bipolar transistor (RC-IGBT) with discontinuous field-stop (DFS) layer is proposed and investigated. The DFS increases the distributed resistance near the collector side in the unipolar mode; and thus, eliminates the snapback phenomenon with a reduced half-cell pitch of 60 mu m. In the blocking state, the depletion region is pinched off by the DFS and thus punchthrough is avoided, ensuring high breakdown voltage of 1200 V. The DFS RC-IGBT shows higher short-circuit ruggedness and increases the short-circuit duration time by30% compared with the conventional RC-IGBT due to the decreased base transport factor. The proposed structure also achieves better tradeoff between turn-OFF loss and forward voltage drop. For the same forward voltage drop, the turn-OFF loss is reduced by 30%.