A new SPICE model of the bipolar transistor including avalanche multiplication and current crowding effects is described. Impact-ionization phenomena are modelled refering 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 RB is included in the model and described exactly. The model also allows one to easily include high injection effects, which are important for the evaluation of breakdown voltage at high IE.
A physics-based, accurate spice model of impact-ionization effects in bipolar transistors
ZANONI, ENRICO;MENEGHESSO, GAUDENZIO;
1994
Abstract
A new SPICE model of the bipolar transistor including avalanche multiplication and current crowding effects is described. Impact-ionization phenomena are modelled refering 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 RB is included in the model and described exactly. The model also allows one to easily include high injection effects, which are important for the evaluation of breakdown voltage at high IE.Pubblicazioni consigliate
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