Patent ID: 8518797

Claim:
A method for manufacturing an SOI substrate comprising the steps of: forming an oxide film over an entire surface of a single crystal semiconductor substrate by performing heat treatment; adding a first ion to the single crystal semiconductor substrate by irradiation of the single crystal semiconductor substrate with a planar, linear, or rectangular ion beam without mass separation through the oxide film, so that a separation layer is formed; adding a second ion subjected to mass separation to parts of the separation layer formed in the single crystal semiconductor substrate by scanning with a spot ion beam, so that at least two high concentration regions each having a linear shape are formed in parallel to each other; disposing one surface of the single crystal semiconductor substrate and a surface of a base substrate to face each other in order to bond a surface of an insulating layer formed over the single crystal semiconductor substrate and the surface of the base substrate; and cleaving the single crystal semiconductor substrate using the separation layer as a cleavage plane, so that a single crystal semiconductor layer is formed over the base substrate, wherein a mass number of the second ion is the same as or larger than a mass number of the first ion.