Method of processing of nitride semiconductor wafer, nitride semiconductor wafer, method of producing nitride semiconductor device and nitride semiconductor device

Abstract

A nitride semiconductor wafer is planar-processed by grinding a bottom surface of the wafer, etching the bottom surface by, e.g., KOH for removing a bottom process-induced degradation layer, chamfering by a rubber whetstone bonded with 100 wt %-60 wt % #3000-#600 diamond granules and 0 wt %-40 wt % oxide granules, grinding and polishing a top surface of the wafer, etching the top surface for eliminating a top process-induced degradation layer and maintaining a 0.5 μm-10 μm thick edge process-induced degradation layer.

1 - 12 . (canceled) 
     
     
         13 . A method of processing a nitride semiconductor wafer comprising the steps of:
 flat-processing a bottom surface of the nitride semiconductor wafer;   eliminating a process-induced degradation layer on the bottom surface by etching;   chamfering an edge of the wafer by a diamond-bonded whetstone;   flat-processing a top surface of the wafer;   eliminating a process-induced degradation layer on the top surface by vapor-phase etching; and   maintaining a 0.5-10 μm thick edge process-induced degradation layer remaining on the edge.   
     
     
         14 . A method of processing a nitride semiconductor wafer comprising the steps of:
 slicing a nitride semiconductor crystal ingot into nitride semiconductor wafers;   eliminating a process-induced degradation layer on a bottom surface by etching;   chamfering an edge of the wafer by a diamond-bonded whetstone;   flat-processing a top surface of the wafer;   eliminating a process-induced degradation layer on the top surface by vapor-phase etching; and   maintaining a 0.5-10 μm thick edge process-induced degradation layer remaining on the edge.   
     
     
         15 . The method of processing a nitride semiconductor wafer as claimed in  claim 13  or  14 , wherein the whetstone of chamfering is a rubber-bonding or bubbled-resin-bonding whetstone which includes #3000-#600 diamond granules at 100 wt %-60 wt % and oxide granules at 0 wt %-40 wt % and is bonded to a base plate by the rubber or bubbled resin. 
     
     
         16 . The method of processing a nitride semiconductor wafer as claimed in  claim 15 , wherein the oxide granules are Fe 2 O 3 , Cr 2 O 3 , MnO 2 , ZnO, CuO, CO 3 O 4  or Fe 3 O 4 . 
     
     
         17 . A method of processing a nitride semiconductor wafer comprising the steps of:
 grinding a bottom surface of a gallium nitride wafer;   inducing a process-induced degradation layer on the bottom surface;   etching away the bottom process-induced degradation layer with any one of KOH, NaOH and H 3 PO 4  solutions;   chamfering an edge of the gallium nitride wafer by a rubber-bonding whetstone;   inducing an edge process-induced degradation layer on the edge;   grinding a top surface of the gallium nitride wafer;   inducing a process-induced degradation layer on the top surface;   rough-polishing the top surface with rough whetting granules;   fine-polishing the top surface with fine whetting granules;   eliminating a part of the edge process-induced degradation layer; and   maintaining a 1-3 μm thick edge process-induced degradation layer on the edge.