| 摘要 |
PURPOSE: To enable manufacturing a plurality of kinds of transistors without increasing the number of processes, by forming oxide films different in thickness, on exposed emitter forming regions different in width, by a normal pressure CVD method, and forming impurity regions different in concentration by implanting ions from above the oxide films. CONSTITUTION: A polycrystalline silicon film 21 and an oxide film 23 are formed on the surface of a semiconductor substrate. In the emitter forming regions, the films 21 and 22 are so eliminated that the sectional width is 1μm for a transistor of high speed operation, and the sectional width is 10μm for a transistor for current amplification. An oxide film 34 is formed on the exposed semiconductor substrate surface by a normal pressure CVD method. The thickness of the oxide film 34 corresponding to the width of 1μm is about 50nm, and the thickness of the oxide film 34 corresponding to the width of 10μm is about 400nm. By ion-implanting 35 N-type impurities from above the oxide film 34, a heavily doped collector region is formed in the semiconductor substrate, for the film thickness of 50nm, and is not formed for the film thickness of 400nm.
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