| 摘要 |
PURPOSE:To obtain a good single crystal by a method wherein a part of non- single crystal semiconductor region is coated with an interference thin film so that more flux of light can be absorbed at the regional periphery part than at the center. CONSTITUTION:SiO2 3 that is formed at a non-single crystal Si region 2 on SiO2 1 has a small hole 4. The product of the thickness of a film 3 by its refractive index (optical film thickness) is approximated to 1/4 wave length of the Ar laser beam. With the Ar laser irradiated vertically on the film 3, the reflection factor will be the minimum value, approximately 8%, because of interference. At the hole 4, the non-single crystal Si 2 exposes and the reflection factor will be approximately 38%. 92% of the laser beam that reaches the region 2 by irradiating vertically reaches under the film 3; 62%, at the hole part. The temperature of the hole part is lower than the surroundings. After this lowest temperature part is heated to a little over the fusing point of non-single crystal, Si, if this part is cooled, the center of the hole 4 will have the lowest temperature. Recrystaillization progresses toward the perimeter from this center and the region 2 is single a crystallized, which is fairly advantageous for forming a single crystalon crystal substrate. |
