As discussed in Chap. 5, the silicon insulated gate bipolar transistor (IGBT) has been a highly successful innovation that has been widely accepted by the industry for power control applications with supply voltages ranging from 300 to 6,000 V. As shown in that chapter, the optimization of the IGBT structure from an applications standpoint requires reduction of the lifetime in the drift region to enhance its switching speed. This is accompanied by a significant increase in the on-state voltage drop for the IGBT structure. The large on-state voltage drop in the IGBT structure for smaller lifetime values in the drift region can be traced to poor conductivity modulation of the drift region near the emitter. A superior on-state carrier distribution can be obtained by utilizing thyristor-based on-state current flow as shown in Chap. 2. The gate-turn-off thyristor (GTO) was developed to take advantage of the low on-state voltage drop. However, the gate drive current for the GTO is very large as demonstrated in Chap. 4.