| 摘要 |
PURPOSE:To obtain a uniform surface state in performing epitaxial growth while starting crystallization from the polysilicon layer in window forming portions, by performing the crystallization of the window forming portions separately from crystallization of other portions such that the window forming portions are first crystallized and then the whole surface of the polysilicon layer is single-crystallized from the first crystallized portions as the nuclei. CONSTITUTION:An SiO2 layer 2 on an Si wafer 1 is provided with linear window forming portions 5 spaced from each other with a certain distance, and a polysilicon layer is deposited thereon by CVD or the like. The broken lines indicate the positions of the window forming portions 5 while the solid lines indicate recessed regions 6 produced on the polysilicon layer 4. The space between the linearly provided window forming portions 5 depends upon the size of a device to be formed. The beam diameter is controlled to a several mum with the power of Ar laser at 10W, and such laser beam is applied along the linear window forming portions 5 so as to single crystallize the polysilicon layer in the window forming portions 5. The laser power is then decreased to 5W while the diameter of the spot is increased, and such laser beam is made to scan in the rectangular direction against the linear window forming portions 5 so as to crystallize the polysilicon layer 4 on the SiO layer 2. |
