Patent ID: 6818492
Filing Date: 2004-11-16
Classification: H01L

Abstract:
A method for manufacturing a semiconductor device comprising:doping impurities of a first conducting type into a surface of a collector layer of a second conducting type and thermally diffusing the impurities of the first conducting type to form a base region of the first conducting type in the surface of the collector layer; forming a base electrode layer on a surface of the base region and forming an insulating film on a surface of the base electrode layer; forming a trench, which does not reach the collector layer, by etching the base region through an opening created at part of the base electrode layer and the insulating film and forming a sidewall on an inside wall of the trench; forming a polysilicon layer containing impurities for emitter diffusion inside the trench; forming an emitter region by diffusing the impurities of the polysilicon layer; and forming a through hole in the insulating film, forming a base electrode contacting the base electrode layer through the through hole and forming an emitter electrode contacting the polysilicon layer.