Discussions and extension of van Vliet's noise model for high speed bipolar transistors

The general van Vliet noise model for transistors was derived for base minority carriers only under adiabatic boundary conditions. This paper extends the model by including the emitter minority carrier noise and the base-collector space charge region (CB SCR) effects based on the mathematical framework developed by van Vliet. Both the finite surface recombination velocity at polysilicon emitter and the finite carrier exit velocity at CB SCR are considered. It is proved that the van Vliet model can be directly used to include the emitter minority carrier noise, and the model holds when the two finite velocity boundary conditions are imposed. A new set of equations are derived to include the effect of CB SCR delay on noise.