Gallium nitride crystal substrate and method of producing same

Abstract

A low-distortion gallium nitride crystal substrate including low dislocation single crystal regions (Z) having a definite c-axis and a definite a-axis, C-plane growth regions (Y) having a c-axis and a-axis parallel to the c-axis and a-axis of the low dislocation single crystal regions (Z), voluminous defect accumulating regions (H) having a c-axis inverse to the c-axis of the low dislocation single crystal regions (Z) and an a-axis parallel with the a-axis of the low dislocation single crystal regions (Z), and 0.1/cm 2 to 10/cm 2 c-axis gross core regions (F) containing at least one crystal having a c-axis parallel to the c-axis of the low dislocation single crystal regions (Z) and an a-axis different from the a-axis of the low dislocation single crystal regions (Z).

1 - 6 . (canceled) 
   
   
       1 . A gallium nitride crystal substrate comprising:
 low dislocation single crystal regions (Z) having a definite c-axis and a definite a-axis;   C-plane growth regions (Y) having a c-axis and an a-axis parallel to the c-axis and the a-axis of the low dislocation single crystal regions (Z);   voluminous defect accumulating regions (H) having a c-axis inverse to the c-axis of the low dislocation single crystal regions (Z) and an a-axis parallel with the a-axis of the low dislocation single crystal regions (Z); and   random defect bundle regions (G) of densities between 0/cm 2  and 100/cm 2 .   
   
   
       2 . The gallium nitride crystal substrate as claimed in  claim 1  further comprising:
 0.1 cm 2  to 10/cm 2  c-axis gross core regions (F) containing at lease one crystal having a c-axis parallel to the c-axis of the low dislocation single crystal regions (Z) and an a-axis different from the a-axis of the low dislocation single crystal regions (Z).   
   
   
       3 . The gallium nitride crystal substrate as claimed in  claim 1 , wherein a distortion curvature radius of the gallium nitride crystal substrate is from 150 cm to 1800 cm. 
   
   
       4 . A gallium nitride crystal substrate comprising:
 low dislocation single crystal regions (Z) having a definite c-axis and a definite a-axis;   C-plane growth regions (Y) having a c-axis and an a-axis parallel to the c-axis and the a-axis of the low dislocation single crystal regions (Z); and   voluminous defect accumulating regions (H) having a C-axis inverse to the c-axis of the low dislocation single crystal regions (Z) and an a-axis parallel with the a-axis of the low dislocation single crystal regions (Z);   characterized in that a distortion curvature radius of the gallium nitride crystal substrate is from 150 cm to 1800 cm.