III-V group nitride system semiconductor self-standing substrate, method of making the same and III-V group nitride system semiconductor wafer

Abstract

A III-V group nitride system semiconductor self-standing substrate is made of III-V group nitride system semiconductor single crystal with a hexagonal crystal system crystalline structure. The substrate is provided with a surface that is off-oriented 0.09 degrees or more and 24 degrees or less in the a-axis or m-axis direction from C-face of the substrate.

1 . A III-V group nitride system semiconductor self-standing substrate, comprising: 
 III-V group nitride system semiconductor single crystal with a hexagonal crystal system crystalline structure,    wherein the substrate is provided with a surface that is off-oriented 0.09 degrees or more and 24 degrees or less in the a-axis direction from C-face of the substrate.    
   
   
       2 . A III-V group nitride system semiconductor self-standing substrate, comprising: 
 III-V group nitride system semiconductor single crystal with a hexagonal crystal system crystalline structure,    wherein the substrate is provided with a surface that is off-oriented 0.09 degrees or more and 24 degrees or less in the m-axis direction from C-face of the substrate.    
   
   
       3 . The III-V group nitride system semiconductor self-standing substrate according to  claim 1 , wherein: 
 the off-orientation has an in-plane dispersion of within ±1 degree and the minimum off-orientation is 0.09 degrees or more and the maximum off-orientation is 24 degrees or less.    
   
   
       4 . The III-V group nitride system semiconductor self-standing substrate according to  claim 2 , wherein: 
 the off-orientation has an in-plane dispersion of within ±1 degree and the minimum off-orientation is 0.09 degrees or more and the maximum off-orientation is 24 degrees or less.    
   
   
       5 . The III-V group nitride system semiconductor self-standing substrate according to  claim 1 , wherein: 
 the III-V group nitride system semiconductor is represented by In x Ga y Al 1-x-y N (0≦x≦1, 0≦y≦1, 0≦x+y≦1).    
   
   
       6 . The III-V group nitride system semiconductor self-standing substrate according to  claim 2 , wherein: 
 the III-V group nitride system semiconductor is represented by In x Ga y Al 1-x-y N (0≦x≦1, 0≦y≦1, 0≦x+y≦1).    
   
   
       7 . A method of making a III-V group nitride system semiconductor self-standing substrate, comprising the steps of: 
 proving a hetero-substrate with a surface off-oriented in a specific direction from a low index surface of the substrate;    growing an epitaxial layer of III-V group nitride system semiconductor single crystal on the hetero-substrate; and    separating the epitaxial layer from the hetero-substrate to have the III-V group nitride system semiconductor self-standing substrate with a predetermined off-orientation.    
   
   
       8 . The method according to  claim 7 , wherein: 
 the hetero-substrate is a sapphire substrate that has a surface inclined in a specific direction from C-face of the substrate.    
   
   
       9 . The method according to  claim 8 , wherein: 
 the specific direction is the m-axis direction of sapphire.    
   
   
       10 . The method according to  claim 8 , wherein: 
 the specific direction is the a-axis direction of sapphire.    
   
   
       11 . The method according to  claim 7 , wherein: 
 the hetero-substrate is a sapphire substrate that has a surface inclined 0.07 degrees or more and 20 degrees or less in the m-axis direction from C-face of the substrate.    
   
   
       12 . The method according to  claim 7 , wherein: 
 the hetero-substrate is a sapphire substrate that has a surface inclined 0.07 degrees or more and 20 degrees or less in the a-axis direction from C-face of the substrate.    
   
   
       13 . A method of making a III-V group nitride system semiconductor self-standing substrate, comprising the steps of: 
 growing a first single-crystal gallium nitride film on a sapphire substrate with an off-orientation;    depositing a metal film on the single-crystal gallium nitride film;    heating the substrate with the metal film deposited in atmosphere including hydrogen gas or hydrogenated gas to form a void in the first single-crystal gallium nitride film;    depositing a second single-crystal gallium nitride film with an off-orientation thereon; and    separating the second single-crystal gallium nitride film from the substrate to have a gallium nitride self-standing with an off-orientation.    
   
   
       14 . A III-V group nitride system semiconductor wafer, comprising: 
 a self-standing substrate that has a hexagonal crystal system crystalline structure and is provided with a surface that is off-oriented 0.09 degrees or more and 24 degrees or less in the a-axis or m-axis direction from C-face of the substrate; and    a III-V group nitride system semiconductor layer that is homo-epitaxially grown on the self-standing substrate.