Process for producing a semiconductor substrate

Claim 1

A process for producing a semiconductor substrate, comprising successively the steps of: a) anodizing a surface layer on one side of a single-crystal semiconductor substrate to make the surface layer porous to form a porous single-crystal semiconductor layer on a non-porous single-crystal semiconductor region; b) expitaxially growing a non-porous single-crystal semiconductor layer on said porous single-crystal semiconductor layer; c) bringing the surface of said non-porous single-crystal semiconductor layer into close contact with the surface of an insulator substrate and then bonding both to each other without heating; d) grinding down said non-porous single-crystal semiconductor region to remove part of said non-porous single-crystal semiconductor region; e) heating the whole to strengthen the bond between said non-porous single-crystal semiconductor layer and said insulator substrate; f) etching said non-porous single-crystal semiconductor region remaining after the grinding step d), to entirely remove said non-porous single-crystal semiconductor region to expose said porous single-crystal semiconductor layer; and g) selectively etching said porous single-crystal semiconductor layer to remove said porous single-crystal semiconductor layer.