Modeling of high-injection effects in bipolar devices

An analytical model for minority-carrier transport and recombination in quasi-neutral regions at arbitrary injection levels is presented. The proposed approach retains a general dependence of the transport parameter on the doping concentration, and can be thus applied to arbitrary doping profiles. It also includes heavy doping effects and injection-dependent recombination mechanisms. Simple closed-form analytical expressions are derived for the minority-carrier currents in bipolar transistors, and for the effective recombination velocity of high-low junctions