| 摘要 |
PURPOSE:To miniaturize a transistor, by implanting ions through a silicon nitride film, which is formed on a substrate. CONSTITUTION:An element isolating and selecting oxide film 12 is grown to a thickness of 0.8mum. Thereafter, a gate oxide film 13 is grown to 400Angstrom by thermal oxidation. A polycrystalline silicon gate electrode 14 is formed so as to have a thickness of 4,000Angstrom and a gate length of 1.5mum. Thereafter, the polycrystalline silicon gate is oxidized by about 500Angstrom for insulation, and a polycrystalline silicon oxide film 15 is formed. Then, a silicon nitride film 16 is grown by 0.15mum by a CVD method. At this time, an ion implanting mask having the total thickness of 0.2mum is formed on the side surface of the polycrystalline silicon gate electrode. The film thickness is sufficiently small in comparison with 0.4-0.6mum in a conventional method. Therefore, offset is hard to occur beneath the gate electrode. Then, as impurities for forming source and drain regions, boron ion beams 17 are implanted. The energy of the ions is 40keV and the amount of dose is 3X10<15>/cm<2>.
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