| 摘要 |
PURPOSE:To obtain an SOS substrate having superior crystallinity even when a silicon film is thin and having satisfactorily few microtwins by a method wherein the process that the SOS substrate made the single crystal silicon film of the prescribed thickness to grow is heat treated at a temperature higher than the growth temperature and moreover in an oxygen atmosphere, and thus formed oxide film is removed, is repeated up to reach the desired silicon film thickness. CONSTITUTION:A single crystal silicon film 2 is grown epitaxially at film thickness of 1mum or more on a single crystal sphhire substrate 1. As the growth condition, SiH4 gas is used, the growth temperature is made to 950 deg.C, and the growth speed is made to 1mum/min, for example. Then, the heat treatment temperature is selected to 1,100 deg.C as the temperature higher than the growth temperature 950 deg.C, and the heat treatment is performed in an oxigen atmosphere for 1.5hr. An oxide film generated by the heat treatment thereof is etched to be removed by a dilute hydrofluoric acid liquid. The silicon film 2 is thinned as much. The heat treatment and etching thereof are repeated for the 10 cycles in total, and thickness of the silicon film is made to the necessary thickness finally. |
