| 摘要 |
PURPOSE:To obtain a MOS transistor which has reduced a drain leak current and improved mobility by allowing a semiconductor film to grow on an insulated substrate, and after executing ion implantation of yttrium and lanthanoids metal and oxygen into the area near the interface converting them into insulator material through heat processing. CONSTITUTION:After formation of a silicon film 22 on a sapphire substrate 21 by the epitaxial growth, a SiO2 film 23 and a Si3N4 film 24 are sequentially formed thereon, YC3 ion is implanted to a silicon film 22 through the Si3N4 film and SiO2 film 23 by adjusting the acceleration energy and dose amount, and moreover oxygen is also implanted. A field oxide film 27 is formed on the etching portion of silicon film 22 through the heat oxidation process for 10hr at 900 deg.C and a gate oxide film 29 is formed through the heat processing for an hour at 950 deg.C. An insulator layer 30 is formed through reaction between yttrium, silicon and A with oxygen by two times of heat processings. As compared with an n-channel MOS/SOS wherein any insulator layer is not formed at the interface, a drain current is reduced by the order of about two figures.
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