Method for manufacturing soi substrate

A method for manufacturing an SOI substrate comprising the steps of:

• irradiating a single crystal semiconductor substrate with accelerated ions to form an embrittlement region in the single crystal semiconductor substrate;
• bonding the single crystal semiconductor substrate and a base substrate together with an insulating layer interposed therebetween;
• separating the single crystal semiconductor substrate at the embrittlement region to form a single crystal semiconductor layer over the base substrate with the insulating layer interposed therebetween;
• and
• irradiating a surface of the single crystal semiconductor layer with a laser beam in a chamber which is subjected to deoxidation treatment and set to a reducing atmosphere to melt at least a surface portion of the single crystal semiconductor layer to recrystallize the single crystal semiconductor layer.

A method for manufacturing an SOI substrate comprising the steps of:

• irradiating a single crystal semiconductor substrate with an ion accelerated to form an embrittlement region in the single crystal semiconductor substrate;
• bonding the single crystal semiconductor substrate and a base substrate together with an insulating layer interposed therebetween;
• separating the single crystal semiconductor substrate at the embrittlement region to form a single crystal semiconductor layer over the base substrate with the insulating layer interposed therebetween;
• and
• irradiating a surface of the single crystal semiconductor layer with a laser beam in a chamber which is subjected to deoxidation treatment and set to a reducing atmosphere to melt at least a surface portion of the single crystal semiconductor layer to recrystallize the single crystal semiconductor layer,
• wherein a depth of a melted portion of the single crystal semiconductor layer formed by irradiation with the laser beam is shallower than the thickness of the single crystal semiconductor layer.