Numerical investigate of base doping for minimum base transit time

In this paper numerical optimum base doping for minimum base transit time is presented. The bandgap-narrowing effect, high-injection effect, and carrier velocity saturation at the base edge of the base collector junction, and also doping and field dependence of mobility, are considered. Many doping profile are investigated including, linear, exponential doping concentration, we assumed uniform, exponentially and Gaussian doping profiles. Base transit time is investigated numerically for optimum base doping profile.