QUPETS - A simulator for polysilicon-contacted emitter bipolar transistors

The use of polysilicon as a contact to the emitter of a bipolar transistor has been shown to improve its current gain performance. A two-dimensional device simulator using a finite difference formulation of the semiconductor equations?? solved using a Gummel algorithm has been developed. The simulator incorporates a modified form of the basic equation set which describes the effect of grain boundaries in the polysilicon region of the device. The program has been used to investigate and evaluate the major factors contributing to gain enhancement due to the polysilicon contact, namely polysilicon doping density and thickness, the single-crystal emitter region depth, and polysilicon-single crystal silicon interface and grain boundary properties. Simulated results are compared with measurements taken from manufactured devices.