| 摘要 |
PURPOSE:To improve the gate withstand voltage as well as to contrive ultramicroscopic formation of the titled semiconductor device by eliminating its excessive space by a method wherein SiO2 films are provided on the side face of the Si island of an insulating substrate by performing a self-matching. CONSTITUTION:When an Si film is superposed on the sapphire substrate 10 and an anisotropic etching is performed using an SiO2 mask, an Si island 20 with its side face inclining approximately 60 degrees can be formed. The island is oxidized at a high temperature in O2 and covered by SiO2. A CVD SiO223 film is superposed on the above and resist 24 is applied thereon. Said resist 24 is to be applied thicker at the base region of the island than the other part due to having a stepping. Under the above condition, a reactive ion is etched, the resist on the flat part is completely removed, and the SiO2 films 21 and 23 which are exposed by NH4F are removed by etching. The side face of the island is still thickly covered by the SiO2 films 21 and 23, the resist 24 is removed, a gate oxide film 25 is formed, and the semiconductor device is completed. According to this constitution, the gate withstand voltage can be improved, and the entire upper surface of the island can be used effectively, thereby enabling to form the element into an ultramicroscopic state. |
