| 摘要 |
PROBLEM TO BE SOLVED: To uniformly etch a base silicon film, when the emitter electrode of a bipolar transistor is formed. SOLUTION: A base polysilicon film 19 is selectively oxidized, impurities are introduced through the intermediary of this oxide film for the formation of an intrinsic base region 15, and the oxide film on an emitter region is etched to form a sidewall 21b. Impurities are introduced using the sidewall 21b to form an emitter region 16. With this setup, the surface of the intrinsic base region 15 of the base silicon film can be etched accurately when a sidewall is formed, and the emitter region can be set uniform in area, so that a semiconductor device of this design with reduced dispersion and little fluctuation in electrical characteristics such as contact resistance and VBE can be obtained.
|
