| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device in which a vertical bipolar transistor with high performance and high power consumption and another vertical bipolar transistor with low power consumption can be obtained at the same time without a photo lithography step. SOLUTION: An n--type epitaxial silicon layer 3 for collector is formed on the surface of an n+-type silicon substrate 21 having a crystal plane azimuth of (100), and a silicon oxide layer 4 made by the LOCOS method is formed thereon. A p+-type polysilicon film 7 for base electrode for a vertical bipolar transistor is selectively formed thereon, and openings 101 and 102 made of p+-type polysilicon film 7 for base electrode are formed thereon. In this case, the bipolar opening 101 for high breakdown strength is made smaller than the bipolar opening 102 for high speed. The upper surface of the p+-type polysilicon film 7 for base electrode and the side thereof are covered with a silicon nitride film 8 and a silicon oxide film 11, respectively.
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