Abstract: The technology and structure of the polysilicon emitter is one of the important bases of modern advance silicon bipolar transistors operation for low temperatures. As for samll dimensional polysilicon bipolar transistors, and nuder the approximations of neglecting the recombination in the crystal emitter and base region, a nonlinear one dimension analytical model for emitter injecting alection current density J_n and for base injecting hole current density J_ps are proposed based on the combining effects of tunneling and recombination mechanism in the polysilicon and single crystal interface. The model is available for low temperature operation and different biased conditions, providing a quick, convenient and high precision tool for D. C. and A. C. proformances simulation and can be used as an important supplement to the multi-dimensional numerical modeling In guiding the optimization design for low temperature devices.

Key words: polysilicon emitter, current transportation, low temperature, BJT