Group iii nitride substrate, semiconductor device comprising the same, and method for producing surface-treated group iii nitride substrate

Abstract

A group III nitride substrate in one embodiment has a surface layer. The surface layer contains 3 at. % to 25 at. % of carbon and 5×10 10 atoms/cm 2 to 200×10 10 atoms/cm 2 of a p-type metal element. The group III nitride substrate has a stable surface.

1 - 4 . (canceled) 
     
     
         5 . A Group III nitride substrate, comprising a surface layer, wherein
 the surface layer contains carbon of 3 at. % to 25 at. % and a p-type metal element of 5×10 10  atoms/cm 2  to 200×10 10  atoms/cm 2 , and   oxygen concentration in the surface layer is 3 at. % to 15 at. %.   
     
     
         6 . The Group III nitride substrate according to  claim 5 , wherein the surface layer further contains an insulating metal element of 1×10 10  atoms/cm 2  to 100×10 10  atoms/cm 2 . 
     
     
         7 . The Group III nitride substrate according to  claim 5 , Si concentration in the surface layer is 500×10 10  atoms/cm 2  to 8000×10 10  atoms/cm 2 . 
     
     
         8 . The Group III nitride substrate according to  claim 5 , a surface roughness of the surface layer is no greater than 3 nm in terms of RMS. 
     
     
         9 . A Group III nitride substrate with an epitaxial layer, comprising the Group III nitride substrate and the epitaxial layer, wherein
 at an interface between the Group III nitride substrate and the epitaxial layer, a number of C atoms per 1 cm 3  ranges from 2×10 16  to 5×10 17 , and a number of atoms of the p-type metal element per 1 cm 3  ranges from 2×10 16  to 1×10 17 .   
     
     
         10 . The Group III nitride substrate with the epitaxial layer according to  claim 9 , wherein a number of O atoms per 1 cm 3  at the interface between the Group III nitride substrate and the epitaxial layer ranges from 2×10 16  to 1×10 18 . 
     
     
         11 . The Group III nitride substrate with the epitaxial layer according to  claim 9 , wherein a number of Si atoms per 1 cm 3  at the interface between the Group III nitride substrate and the epitaxial layer ranges from 1×10 15  to 1×10 19 . 
     
     
         12 . A semiconductor device comprising the Group III nitride substrate with the epitaxial layer defined in  claim 9 .