Method for manufacturing hexagonal semiconductor plate crystal

Abstract

A plate crystal cut from a gallium nitride crystal with a crystal cutting wire, where the plate crystal has a principal face of (20−21), and a magnitude of warpage of the plate crystal is 1.0 μm/mm or less in a line along the perpendicular projection of the c axis on the principal face passing through the center of the principal face.

1 - 9 . (canceled) 
     
     
         10 : A plate crystal cut from a gallium nitride crystal with a crystal cutting wire, wherein the plate crystal has a principal face of (20−21), and a magnitude of warpage of the plate crystal is 1.0 μm/mm or less in a line along the perpendicular projection of the c axis on the principal face passing through the center of the principal face. 
     
     
         11 : The plate crystal according to  claim 10 , wherein the magnitude of warpage of the plate crystal is 0.8 μm/mm or less. 
     
     
         12 : The plate crystal according to  claim 10 , wherein the magnitude of warpage of the plate crystal is 0.5 μm/mm or less. 
     
     
         13 : The plate crystal according to  claim 10 , wherein the magnitude of warpage of the plate crystal is 0.3 μm/mm or less. 
     
     
         14 : The plate crystal according to  claim 10 , wherein the plate crystal has a square shape of 5 mm to 10 mm, and a magnitude of warpage per evaluated length 5 mm of the plate crystal is less than 5 run in the line. 
     
     
         15 : The plate crystal according to  claim 10 , wherein the plate crystal has a disk-like shape. 
     
     
         16 : The plate crystal according to  claim 15 , wherein a maximum diameter of the plate crystal is equal to or more than 10 mm. 
     
     
         17 : The plate crystal according to  claim 15 , wherein a maximum diameter of the plate crystal is equal to or more than 20 mm. 
     
     
         18 : The plate crystal according to  claim 15 , wherein a maximum diameter of the plate crystal is equal to or more than 25 mm. 
     
     
         19 : The plate crystal according to  claim 15 , wherein the plate crystal has diameter of 2 inches, and a magnitude of warpage per evaluated length 50 mm of the plate crystal is less than 40 μm in the line. 
     
     
         20 : The plate crystal according to  claim 19 , wherein the magnitude of warpage per evaluated length 50 mm of the plate crystal is less than 30 μm in the line. 
     
     
         21 : The plate crystal according to  claim 19 , wherein the magnitude of warpage per evaluated length 50 mm of the plate crystal is less than 20 μm in the line.