| 摘要 |
PURPOSE:To reduce a junction capacitance between a collector and a base and to make it possible to form a transistor, which can perform high speed operation, by forming base and emitter regions by a self-aligning manner using one mask. CONSTITUTION:On a silicon substrate 1, an N-type epitaxial layer 2, an SiO2 layer 10, a P<+> polysilicon layer 20 and an SiN layer 30 are formed. With photoresist applied thereon as a mask, the SiN layer 30 and the P<+> polysilicon layer 20 are etched. Thereafter, the photoresist is removed, and the SiO2 layer 10 is removed by wet etching. A P<+> polysilicon layer 40 is formed thereon. The layer 40 undergoes wet etching. Then, oxidation is performed and the P<+> polysilicon layers 20 and 40 and a part of the N-type epitaxial layer are transformed into an oxide film 41. A P<+> diffused part 4 is formed from the P<+> polysilicon layer. Thereafter, the oxide film 41 is removed by anisotropic etching. A P<+> diffused part 5 corresponding to an intrinsic base region is formed. Then, an N-type diffused layer 6 corresponding to an emitter is formed. As an emitter-taking out electrode, a metal layer or an N-type polysilicon layer 50 is formed.
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