| 摘要 |
PURPOSE:To form a single-crystal thin film without crystal defects on an insulating film by a method wherein the surface of the insulating film is made lower than a substrate single-crystal region which is to be a seed and the gentle transition of substance from the substrate to the insulating film is provided. CONSTITUTION:An SiO2 film 10, an Si3N4 film 11 and a resist film 12 are formed on a region to be a seed of single-crystal growth. After a substrate Si 9 is etched into a slope by unisotropic etchant such as hydrazine, the resist film 12 is removed. Then the whole surface is oxidized and an SiO2 film 12 and an Si3N4 film 13 are formed. The Si3N4 is subjected to unisotropic etching such as reactive sputtering. In this process, the Si3N4 film is removed completely except the sloped part so that the Si3N4 film 11 on the seed and the Si3N4 film 13 on the sloped region are left as the Si3N4 film. When the substrate is subjected to oxidization in this state, as the Si3N4 films work as a mask, the thickness of the SiO2 film is varied on the sloped region so that an SiO2 film 14 which has different thickness at the end part is formed. Then the SiO2 films 10, 12 and the Si3N4 films 11, 13 are removed. A polycrystalline Si film 15 is deposited and then scanned to the direction of an arrow 17 by a laser light 16. |
