Novel buffer engineering: A concept for fast switching and low loss operation of planar IGBT

For the first time, an insulated gate bipolar transistor with a novel buffer is proposed and verified by two-dimensional (2D) mixed device-circuit simulations. The structure of the proposed device is almost identical with that of the conventional IGBT, except for the buffer layer which is formed by employing a three-step, gradually changing doping n+ structure. Compared with the conventional IGBT, the proposed device exhibits better trade-off relation between the conduction and switching losses. The turn-off time is halved from 9.4 μs of the conventional IGBT to 4.5 μs of the proposed device, so the operation speed of the proposed device is greatly improved. Further, the forward blocking voltage is enormously increased from 907 V of the proposed device to 1278 V of the proposed device, which is required for high power operation.