| 摘要 |
PURPOSE:To obtain an SOS device in which the influence of a parasitic transistor and the breakdown of a gate insulating film at the edge part caused by electric field concentration can be eliminated and which has excellent characteristics and can be arranged with high integrity by forming silicon dioxide films on the side surfaces of island shape silicon single crystal thin films. CONSTITUTION:Oxidation-proof films 3 are selectively formed on a silicon single crystal thin film 2 formed on a sapphire substrate 1 by epitaxial growth and the regions of the silicon single crystal thin film 2 which are not covered with the oxidation-proof films 3 are completely removed. After that, silicon dioxide films 4 are formed on the side surfaces of the island shape silicon single crystal thin films 2 in an oxidation atmosphere and the oxidation-proof films 3 are removed. For instance, a silicon nitride film is formed on the silicon single crystal thin film 2 as the oxidation-proof film 3 and the oxidation-proof film 3 is removed except the parts corresponding to the element regions by photoetching. Then the parts of the silicon single crystal thin film 2 which are not covered with the oxidation-proof films 3 are removed with anisotropic etchant to separate the silicon single crystal thin film 2 into island shape regions. Then, after the silicon dioxide films 4 are formed by hot oxidation treatment, the oxidation-proof films 3 are removed by dipping the substrate 1 in hot phosphoric acid solution.
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