Texas Instruments Incorporated
Fabricating transistors with implanting dopants at first and second dosages in the collector region to form the base region

Abstract:

A method to fabricate a transistor, the method comprising: implanting dopants in a semiconductor to form a collector region having majority carriers of a first type; implanting dopants with a first dosage and implanting dopants with a second dosage in the collector region to form a base region having majority carriers of a second type, wherein the second dosage is at a lower energy than the first dosage; forming a gate oxide on the base region; forming a gate material on the gate oxide; forming the gate material and the gate oxide to leave uncovered an emitter area of the base region; and implanting dopants in the emitter area to form an emitter region having majority carriers of the first type.