Process for producing monocrystalline layer on insulator

Claim 1

A process for producing a monocrystalline layer on an insulating layer formed on a front side of a semiconductor substrate having at least one impurity region containing impurities under said insulating layer, comprising the steps of: providing a nonmonocrystalline layer with a back side on said insulating layer over said at least one impurity region in said substrate; and heating a local portion of said nonmonocrystalline layer without causing substantial redistribution of said impurities in said at least one impurity region by irradiating said local portion with two energy beams emitted from two respective rod-like heat sources located apart from and parallel to said substrate, wherein a first of said energy beams irradiates said nonmonocrystalline layer from the front side of said nonmonocrystalline layer with an energy density that is larger than that of the other energy beam, and said other energy beam irradiates either the front side of said nonmonocrystalline layer or a back side of said substrate, while moving said energy beams relative to said nonmonocrystalline layer, wherein said nonmonocrystaline layer is locally melted and transformed to a monocrystalline layer during said moving as a result of the irradiation.