A new SPICE model of the bipolar transistor including avalanche multiplication and current crowding effects is described. Impact-ionization phenomena are modelled referring to a physical description of impact-ionization coefficients, rather than to semi-empirical laws, as in previous models. We show that an accurate analysis of multiplication effects can be obtained only if the influence of impact ionization on current crowding and parasitic base resistance is included in the model and described exactly. The model also allows one to easily include high injections effects, which are important for the evaluation of breakdown voltage at high emitter current.
A physics-based, accurate SPICE model of impact-ionization effects in bipolar transistors / E., Zanoni; A., Dal Fabbro; L., Vendrame; Verzellesi, Giovanni; G., Meneghesso; Pavan, Paolo; A., Chantre. - STAMPA. - (1994), pp. 181-184. (Intervento presentato al convegno European Solid State Device Research Conference (ESSDERC) tenutosi a Edinburgh (UK) nel Sept. 1994).