| 摘要 |
PURPOSE:To obtain a high quality epitaxial layer and thus a high speed device by selectively changing thicknesswise a single crystal semiconductor layer on a single crystal insulating substrate to an insulating layer and using the remaining single crystal layer as a seed. CONSTITUTION:A p type single crsytal Si layer 2 is formed on a sapphire 1, an ion implantation layer 3 is provided in such a manner that the maximum concn. of O2 is obtained at 3,700Angstrom above the layer 2 and an SiO2 layer 4 is formed to each substrate 1 by high temperature treatment in the presence of N2. Using the remaining epitaxial layer 2' as a seed a singlecrystal epitaxial layer 5 is formed. The layer 5 is etched to form an island 5' which is covered by an SiO2 layer 6. By selecting conditions, B ions are implanted into the p layer 5' to control a threshold voltage; after that a poly Si layer is accumulated on the entire surface, a gate electrode 7 is made by patterning, a gate oxide film 8 is formed by etching and n<+> source and drain 9, 10 are formed by As ion implantation and heat treatment. Finally the surface is covered by an SiO2 layer 11 and electrodes 13, 14 are bonded. Since the epitaxial layer 5 has little defects the mobility of electron and positive hole is increased, allowing a high speed MOSIC to be obtained. |
