PURPOSE: To obtain a crystal layer of superior quality which is thin and uniform, and improve the performance of devices, such as IC and LSI, in which the above crystal layer is used, by forming a semiconductor crystal layer on a semiconductor substrate of silicon and the like, via a dielectric layer such as an oxide film.
CONSTITUTION: By means of ion implantation and the like, an amorphous layer is formed under the surface of a semiconductor substrate of silicon and the like, which is directly stuck, via an oxide insulative film, on a second semiconductor substrate as a base. The semiconductor substrate of silicon and the like is eliminated up to the amorphous layer by etching with alkali solution, and the film thickness is made uniform. Then the amorphous layer is recrystallized by heat treatment. By ion implantation of silicon, phosphorus, boron, etc., an amorphous layer is formed in a specified depth under the surface. By using a mirror polishing wafer, a direct junction with other mirror polishing wafer is made. In the case where the amorphous layer is formed by the above-mentioned ion implantation method, recrystallization progresses wherein a single crystal part serves as a seed, and a single crystal layer of superior quality can be obtained by a heat treatment at a temperature higher than or equal to 1100°C, because the surface part is in the state of single crystal and recrystallization progresses at the temperature.