Optimization of Base Profile in Bipolar Transistors Considering Retarding Field in Base, Sheet Resistance and Minority Carrier Velocity Saturation

This work studies the effects of base retarding field, sheet resistance and minority carrier velocity saturation on base transit time for optimal base profile in bipolar devices. An iterative technique is employed to provide a global minimum for the product of transit time and sheet resistance in base. The global minimum in base transit time is achieved for optimum base doping profiles with uniform peak base-doping region extending over most part of base region till the point of deflation of doping concentration.