| 摘要 |
PURPOSE:To make possible to crystallize a semiconductor layer keeping the state of the entire layer defectless by applying photoannealing treatment two times or more in the thickness direction of the semiconductor layer. CONSTITUTION:On the surface of a sapphire substrate 1, an epitaxial silicon layer 2 is formed. In such construction of an SOS, many crystal defects exist on the sapphire silicon boundary while less crystal defects exist on the silicon surface, therefore an amorphous layer 3 is formed by implanting ions of, for example, Ar to the boundary, and by irradiating laser beams to the layer to anneal it, a defectless monocrystalline layer 4 is formed. Next, Ar ions are implanted to the surface of the silicon layer, and by annealing with laser beams, the surface is made defectless and converted into a defectless monocrystalline layer 6. By so doing, the entire silicon layer can be made completely defectless. |
