| 摘要 |
PURPOSE:To prevent a poly silicon resistance element from changing the resistance value in the later heat treatment process, and manufacture a high speed transistor. CONSTITUTION:An N<+> type buried layer 2 and an N-type epitaxial layer 3 are formed on a P-type semiconductor substrate 1. An active layer is isolated by an isolation oxide film 4, and the upper surface of the active layer is covered with a protective oxide film 5. A poly silicon film is formed and doped with impurities. After the resistance value is stabilized by annealing at a sufficient temperature and for a sufficient time, a poly silicon resistance element 7 is formed by patterning. The resistance element is coated with a cover oxide film 8. After a P-type diffusion layer 9 turning to a base is formed by ion implantation, a nitride film 10 is formed by a low pressure CVD method. A contact hole 11 18 formed, an N<+> type poly silicon film 12 is formed, a P<+> type diffusion layer 13 is formed by emitter pushing-in, and then an electrode is formed.
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