Fast-switching and shallow saturation bipolar power transistors using corrugated base junctions

A fast-switching and shallow saturation bipolar power transistor fabrication technology using corrugated base junctions, which does not require additional process steps, is proposed in this paper. Computer simulation shows that less excess minority and majority carriers stored in the base and the collector drift region cause the shallow saturation phenomena of the corrugated base transistors at the conduction stage, and that the corrugated base transistors have lateral built-in electric fields under the base electrode, which accelerate the movement of the minority carriers from the bulk to the surface and promote the recombination of excess electrons and holes in the base region. The turn-off times and the saturation voltages between the collector and the emitter are studied systematically as a function of the base masking oxide widths of the corrugated base region, which agree well with the simulation results.