Design considerations and characteristics of rugged punchthrough (PT) IGBTs with 4.5 kV blocking capability

A new high voltage IGBT concept with a blocking capability exceeding 4.5 kV is presented in this paper. The device features a conventional planar DMOS cell design. To compensate for the lack of injection enhancement at the cathode, the n-base width is minimized for the required blocking voltage employing a punchthrough design. To avoid the problems related to anode shorts embedded in highly conductive stopping layers, low injection efficiency of the p+emitter at the anode is realized with a homogeneous, transparent emitter layer. The properties of the emitter and buffer layers determine the injection efficiency of the anode and the electrical characteristics of the high voltage IGBTs. Experimental devices were demonstrated switching inductive loads at up to 70 A/cm/sup 2/ at 3 kV without using snubbers. These devices have short circuit ruggedness and endure peak power densities of 2 MW/cm/sup 2/ for several microseconds.