question_answer

Why is the base region of a transistor made very thin and lightly doped?

Answer:

                    A thin and lightly doped base region contains a smaller number of majority charge carriers. This reduces the recombination rate of electrons and holes at the base-emitter junction. Most of the majority charge carriers coming from emitter into base immediately get collected by the collector. This reduces base current and increases both collector current and current gain of the transistor.