| 摘要 |
PURPOSE:To stabilize a leading resistance between a base region and a wiring film lead externally from the base region by forming a polysilicon layer by an epitaxial method and using a polishing method for polishing the polysilicon layer. CONSTITUTION:An SiO2 film 22 and an Si nitride film 23 are laminated by a CVD method on an Si substrate 21, a resist film is then formed, with the film as a mask the films 23, 22 are etched, and with the films 23, 22 as masks the substrate 21 is etched to form a recess 24. Then, a polysilicon film 25 is formed by a reduced pressure CVD method on the entire substrate 21. Then, after a resist film is formed on the substrate 21, with the film as a mask the film 25 on the recess 24 is removed by a reactive ion etching method. Then, a polysilicon film 25 is formed by an epitaxially growing method on the substrate 21. Then, after the film 26 on the substrate 21 is polished, the film 23 is also etched away. thus, the surface of the substrate is flatly finished, a contacting area between the base region and the polysilicon wiring film is increased, and a base leading resistance is reduced.
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