| 摘要 |
PURPOSE:To prevent the invasion of impurities from the outside at a semiconductor device by a method wherein directly after formation of a polycrystalline silicon film, the surface of the polycrystalline silicon film thereof is oxidized thermally to form an oxide film for protection. CONSTITUTION:A CVD oxide film 2 is accumulated for about 5,000Angstrom on a quartz substrate 1 at first, and the polycrystalline silicon film 3 is accumulated for about 5,000Angstrom in succession. Moreover the surface of the polycrystalline silicon film 3 mentioned above is oxidized by heating for 30min at 1,100 deg.C to form the oxide film 9 for about 1,000Angstrom thickness. Then a resist film 4 is applied on the surface of the oxide film 9, and the oxide film 9 is etched using the resist 4 formed with opening at the prescribed place as the mask. After the resist film 4 is stripped off, the polycrystalline silicon film 3 is etched using the oxide film 9 as the mask. Moreover, after the surface of the polycrystalline silicon film 3 mentioned above is oxidized by heating for 30min at 1,100 deg.C to form a gate film 5, a polycrystalline silicon film 6 is accumulated moreover on the upper layer at 3,000Angstrom thickness. Then the prescribed place is etched using the polycrystalline silicon film on the gate film as the resist, and a gate electrode 6' is formed. Moreover the oxide film at the source and drain regions is etched to be removed using the polycrytalline silicon film thereof as the mask. |
