Semiconductor device and method of forming p-type nitride semiconductor layer

Abstract

A semiconductor device includes a p-type nitride semiconductor layer, the p-type nitride semiconductor layer including an Al-containing nitride semiconductor layer and an Al-containing compound layer containing Al and C as main constituent elements and provided on the surface of the Al-containing nitride semiconductor layer.

What is claimed is: 
     
         1 . A semiconductor device comprising a p-type nitride semiconductor layer,
 the p-type nitride semiconductor layer comprising:
 an Al-containing nitride semiconductor layer; and 
 an Al-containing compound layer containing Al and C as main constituent elements and provided on a surface of the Al-containing nitride semiconductor layer. 
   
     
     
         2 . The semiconductor device according to  claim 1 ,
 wherein the p-type nitride semiconductor layer comprises a hole accumulation layer in the vicinity of an interface between the Al-containing nitride semiconductor layer and the Al-containing compound layer.   
     
     
         3 . The semiconductor device according to  claim 1 ,
 wherein, in the Al-containing compound layer, a composition ratio of C to Al is in a range of 0.2 to 3.   
     
     
         4 . The semiconductor device according to  claim 1 ,
 wherein the Al-containing compound layer contains O and/or N.   
     
     
         5 . The semiconductor device according to  claim 1 ,
 wherein the Al-containing nitride semiconductor layer is composed of Al X Ga 1-X N (0<X≤1).   
     
     
         6 . The semiconductor device according to  claim 1  comprising:
 a first semiconductor layer having an n-type nitride semiconductor layer, 
 a second semiconductor layer having the p-type nitride semiconductor layer 
 an active layer between the first semiconductor layer and the second semiconductor layer, the active layer containing a nitride semiconductor. 
 
     
     
         7 . The semiconductor device according to  claim 6 ,
 wherein the active layer emits deep ultraviolet light.   
     
     
         8 . The semiconductor device according to  claim 6  comprising:
 a p-electrode provided on a surface of the Al-containing compound layer. 
 
     
     
         9 . The semiconductor device according to  claim 6 ,
 wherein a total thickness of the Al-containing nitride semiconductor layer and the Al-containing compound layer is 10 nm or less.   
     
     
         10 . The semiconductor device according to  claim 1  comprising:
 a drain electrode and a source electrode both provided on or above the Al-containing compound layer, and 
 a gate electrode located between the source electrode and the drain electrode, the gate electrode being provided above the Al-containing compound layer via an insulating film. 
 
     
     
         11 . The semiconductor device according to  claim 1 ,
 wherein a thickness of the Al-containing compound layer is less than 10 nm.   
     
     
         12 . A method of forming a p-type nitride semiconductor layer comprising:
 preparing a base; and   providing a p-type nitride semiconductor layer on or above the base by forming an Al-containing nitride semiconductor layer on or above the base and then forming an Al-containing compound layer containing Al and C as main constituent elements on a surface of the Al-containing nitride semiconductor layer by supplying a source gas including a source gas of Al and a source gas of C.   
     
     
         13 . The method according to  claim 12 ,
 wherein the providing the p-type nitride semiconductor layer comprises:   forming the Al-containing nitride semiconductor layer on or above the base by supplying a source gas containing a source gas of Al and a source gas of N and,   forming the Al-containing compound layer on the surface of the Al-containing nitride semiconductor layer.   
     
     
         14 . The method according to  claim 12 ,
 wherein the providing the p-type nitride semiconductor layer comprises:   forming the Al-containing nitride semiconductor layer on or above the base by supplying a source gas containing a source gas of Al and a source gas of N and,   forming the Al-containing compound layer on the surface of the Al-containing nitride semiconductor layer by supplying the source gas containing the source gas of Al and the source gas of C.   
     
     
         15 . The method according to  claim 12 ,
 wherein, in the preparing the base, the base is disposed at a merging position between a first flow path and a second flow path, and   wherein, in the forming the Al-containing compound layer, the Al-containing compound layer is formed by supplying the source gas of Al from the first flow path and the source gas of C from the second flow path in the forming the Al-containing compound layer.   
     
     
         16 . The method according to  claim 15 ,
 wherein an Al metal is vaporized in the first flow path for the source gas of Al.   
     
     
         17 . The method according to  claim 12 ,
 wherein C 3 H 8  is used as the source gas of C.