Forming single crystal silicon on insulator by irradiating a laser beam having dual peak energy distribution onto polysilicon on a dielectric substrate having steps

Claim 1

A process for the production of semiconductor devices, comprising the steps of: (1) forming a first oxide film on a semiconductor substrate; (2) forming a groove structure or groove structures on said first oxide film; (3) forming a first polycrystalline silicon film to serve as an active layer on said first oxide film so as to maintain said groove structures; (4) forming a second oxide film on said first polycrystalline silicon film so as to maintain said groove structures; (5) forming a second polycrystalline silicon film on said second oxide film so as to maintain said groove structures, said second polycrystalline silicon film serving as a buffer layer which absorbs the fluctuation of a scanning laser beam; (6) forming an anti-reflection film on said buffer layer so as to maintain said groove structures; and (7) irradiating said first polycrystalline silicon film through said anti-reflection film, said buffer layer and said second oxide film, with a scanning laser beam having a dual peak type power distribution to melt said first polycrystalline silicon film in such a manner that both peaks in the power distribution of said laser beam are positioned at outer sides of said groove structures, said outer sides of said groove structures corresponding to portions of said first oxide film that are thicker than those portions of said first oxide film with groove structures, thereby achieving a single crystallization of said first polycrystalline silicon film within each of said groove structures in which said semiconductor devices are to be formed.