| 摘要 |
PURPOSE:To obtain substrate electrodes readily from a silicon film even in an SOS device, by using the deposition of a CVD-SiO2 film and a photoetching method. CONSTITUTION:An SOS substrate is prepared by forming a silicon semiconductor layer 2 on a sapphire substrate 1. The silicon semiconductor layer 2 is thermally oxidized and an SiO2 film 3 is grown. Then an Si3N41 film 4 is deposited. Thereafter the Si3N4 film 4 and the SiO2 film 3 are sequentially etched, and a silicon layer 2' is exposed. Then the silicon 2' is etched and the CVD-SiO2 film 6 is deposited. A photoresist film 7 is provided, the Si2N4 film is exposed by a selective etching, and the photoresist film 7 is removed. Thereafter the Si3N4 film 4 is etched until the SiO2 film 3 is exposed. Then the CVD-SiO2 film 6 is removed, and the entire body is oxidized until the silicon film 2' is completely oxidized. A field oxide film 3' is formed and an element region is insulated and isolated. |
