Patent ID: 6887765

Claim:
A method of manufacturing a bipolar junction transistor, comprising: implanting a first base dopant in a semiconductor substrate; after implanting the first base dopant, annealing the semiconductor substrate; forming a first oxide layer outwardly from the semiconductor substrate; forming a first nitride layer outwardly from the first oxide layer; etching a first portion of the first nitride layer and the first oxide layer to form an emitter region; forming an emitter polysilicon layer on the semiconductor substrate; after forming the emitter polysilicon layer, annealing the semiconductor substrate; implanting an emitter dopant in the emitter polysilicon layer; etching a portion of the emitter polysilicon layer, a second portion of the first nitride layer and the first oxide layer to form an emitter polysilicon region having sidewalls; forming nitride regions on the sidewalls; implanting a second base dopant in the semiconductor substrate; and after implanting the second base dopant, annealing the semiconductor substrate to form an emitter and highly-doped base regions.