| 摘要 |
PURPOSE:To convert a polycrystalline silicon film containing oxygen into a film fit for a surface protective film by a method wherein the polycrystalline silicon film containing high percentage of oxygen produced by chemical reaction of SiH4 and N2O in nitrogen atmosphere is heat-treated in nitrogen atmosphere containing steam. CONSTITUTION:A P-type base region 2, an N<+> type emitter region 3 and N<+> type collector electrode regions 4 are formed on an N-type silicon substrate 1. Next, an SiO2 film 5 is removed leaving parts thereof on the emitter region 3 and the emitter.base regions 2, 3. Then a polycrystalline silicon film 6 containing 20-30% of oxygen is formed on overall surface. This polycrystalline silicon film is formed by chemical reaction of SiH4 and N2O in nitrogen atmosphere. Further, the silicon substrate 1 containing the polycrystalline silicon film 6 is heat-treated in a furnace at a temperature exceeding 800 deg.C. Through the heat-treatment, an SiO2 film of around 0.08mum thick is formed to provide the polycrystalline silicon film with high resistance.
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