A novel insulated gate bipolar transistor (IGBT) entitled NPN aided fast switching IGBT (NFS-IGBT) with a P-buffer layer is presented, which enhances the switching speed greatly. Compared with the conventional IGBT, double sided NPN structure is incorporated into the anode to facilitate the turn-off process. The proposed structure is verified by two-dimensional mixed device-circuit simulation, which indicates that the turn-off time is drastically reduced to one third of the conventional value at the expense of acceptable increase of on-state voltage drop. The tradeoff performance also shows great improvement for the new structure.