JPS6425469A - Manufacture of bipolar type semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To obtain a bipolar type semiconductor integrated circuit device which can be operated at a high speed with low power consumption by forming a total base region including an inactive base in a region of a polycrystalline silicon. CONSTITUTION:An N<+> type buried diffused layer 12 an N<-> type epitaxial layer 13, an isolating oxide film 14, and an N<+> type collector region 15 are formed on a P<-> type silicon substrate 11. A CVD oxide film 18 by thermal oxidation, a polycrystalline silicon 17' and an oxide film 16 are selectively removed substantially perpendicularly to the substrate face, part of the layer 13 is exposed, a polycrystalline silicon 17'' is formed. The silicon 17'' is perpendicularly etched, the silicon 17'' remains only on the sidewalls of three layers 16, 17', 18, heat treated, and a P<+> type inactive base 19 is formed on the layer 13. A thin oxide film 20 is formed on the layer 13 by thermally oxidizing at a low temperature, and P-type active base 21 is formed thereunder. The film 20 is removed, a polycrystalline silicon 22 is formed, heat treated to form an N<+> type emitter 23.