Transit time in the base region of drift transistors considering diffusion, recombination, and variable built-in electric field

The present work gives detailed analysis of the transit time of injected minority carriers in the base region of drift transistors, taking into consideration the effect of recombination as well as the variations in the built-in electric field. Some useful impurity-density distributions in the base region are analyzed in detail. Graphs of transit time for these distributions under different conditions are given. The work also includes the distribution that yields minimum transit time for a specified field parameter.