| 摘要 |
PURPOSE:To obtain insulation breakdown strength characterized by an excellent configuration and high reliability, by oxidizing a polysilicon film, removing a deposited oxide film, and thereafter oxidizing the film again. CONSTITUTION:On a semiconductor silicon substrate 1, a silicon oxide film 2 and a silicon nitride film 3 as a capacitor insulating film are deposited. A polycrystalline silicon film 4 as a capacitor plate for a D-RAM and a silicon oxide film 5 used as an insulating film are deposited thereon. Then the first oxidation is performed. At this time, the upper end part of the polycrystalline silicon film 4, which has a large are that is exposed to an oxidizing atmosphere, is readily changed into a silicon oxide film 6. The polycrystalline silicon film 4 is tapered. Conditions are set to prevent that the edge of the polycrystalline film from being lifted by the oxidation. Then, the silicon oxide film 6 is removed, and oxidation is performed again. |
