A design concept for the low forward voltage drop 4500 V trench IGBT

A design concept for a new trench IGBT structure for low forward voltage drop is described. The low forward voltage drop can be achieved by minimizing the p-base region to increase the hole density of the n-base near the emitter side, and by simultaneously keeping MOS channel resistance low. For 4500 V devices, the "triplet" type structure (one p-base every three trenches) is the optimum one, and it improves the forward voltage drop by about 10% over the conventional structure.