Method of recovering and reproducing substrates and method of producing semiconductor wafers

Abstract

A method of recovering a first substrate, including the steps of: sticking a second substrate on a semiconductor layer epitaxially grown on the first substrate; and separating the semiconductor layer and the first substrate. Furthermore, a method of reproducing a first substrate, including the step of surface processing the first substrate separated. Furthermore, a method of reproducing a first substrate, including the step of homoepitaxially growing the first substrate surface processed. Furthermore, a method of producing a semiconductor wafer, including the step of epitaxially growing a semiconductor layer on a first substrate. Thus a group III nitride or similar, expensive substrate can be used to efficiently and economically, epitaxially grow a group III nitride or similar semiconductor layer.

1 - 6 . (canceled) 
   
   
       7 . A method of recovering a first substrate, comprising the steps of:
 sticking a second substrate on a semiconductor layer epitaxially grown on said first substrate; and   separating said semiconductor layer and said first substrate.   
   
   
       8 . A method of producing a semiconductor wafer, comprising the steps of:
 sticking a second substrate on a semiconductor layer epitaxially grown on a first substrate; and   separating said semiconductor layer and said first substrate.   
   
   
       9 . A method of recovering a first substrate formed of a group III nitride, comprising the steps of:
 epitaxially growing a first semiconductor layer on said first substrate;   sticking a second substrate on said first semiconductor layer epitaxially grown on said first substrate; and   separating said first semiconductor layer and said first substrate, the step of sticking including one of: sputtering/vapor-depositing a wax containing one of Ag, Ni, Au, Ge, Ti and an alloy thereof on said first semiconductor layer and then melting said wax, and placing said second substrate thereon and thus sticking said second substrate together; and applying a paste containing one of Ag, Ni, Au, Ge, Ti and an alloy thereof on said first semiconductor layer and placing said second substrate thereon and thus sticking said second substrate together.   
   
   
       10 . A method of reproducing a first substrate formed of a group III nitride, comprising the steps of:
 epitaxially growing a first semiconductor layer on said first substrate;   sticking a second substrate on said first semiconductor layer epitaxially grown on said first substrate;   separating said first semiconductor layer and said first substrate by mechanical slicing such that a portion of said first substrate remains at a surface of said first semiconductor layer;   surface-processing said first substrate separated from said first semiconductor layer after the step of separating; and   homoepitaxially growing a second semiconductor layer on said first substrate separated from said first semiconductor layer when said first substrate is reduced in thickness to no more than 0.6 mrn after the step of surface-processed; wherein   the step of surface-processing is performed by any of mechanical polishing, chemical-mechanical polishing, liquid-phase etching, and vapor-phase etching.