| 摘要 |
PURPOSE:To obtain a smooth surface by a method wherein a polycrystalline Si film is laminated on a substrate having a difference in level according to depressurization CVD process, which is oxidized thermally to an oxidized film. CONSTITUTION:After providing field oxidized film 2, N type source, drain 5, gate oxidized film 6, polycrystalline Si gate electrode and wiring 4 and Si3N4 mask 7 on a P type Si substrate 1, P dropped polycrystalline Si 8 is formed by means of SiH4 and PH3 at 630 deg.C and 0.8torr of gas pressure according to depressurization CVD process. Next, the polycrystalline Si 8 is converted into SiO2 9 through high pressure oxidation at 850 deg.C and 5kg/cm<2> in steam pressure. Then, an opening is provided in the SiO2 film 9 to expose Si3N4 film 7, the film 7 is removed through plasma etching, and an opening 10 is provided in the SiO2 film 6 witg HF aqueous solution. An Al wiring 11 is provided thereafter. According to this method, a difference in level is flattened at the gate electrode or the wiring 4 according to a cubical expansion at the time of conversion into the oxidized film 9, thus preventing disconnection. Moreover, an electrode window same in area can be formed for the presence of Si3N4 film, and a high pressure oxidation can be introduced to save a high temperature treatment. |
