Semiconductor light-emitting element and method of manufacturing the same

Abstract

A transparent electrode is made of a first transparent electrode and a second transparent electrode containing a metal atom whose concentration is 10 wt % or less. The first transparent electrode is provided in a region which is overlapped with a p-side pad electrode when seen in a plane view, and the second transparent electrode is provided in a region except for the region which is overlapped with the p-side pad electrode when seen in the plane view. an electric current injected from the p-side pad electrode is diffused into the second transparent electrode, and is injected efficiently into an active layer in a region except for the region which is overlapped with the p-side pad electrode when seen in the plane view. Therefore, the luminous efficiency increases. Also, a contact resistance between the second transparent electrode and the p-type contact layer is low, the element resistance decreases.

What is claimed is: 
     
         1 . A semiconductor light-emitting element comprising:
 a substrate which has a first surface and a second surface opposite to the first surface;   a semiconductor layer which is formed on the first surface of the substrate;   a first transparent electrode which is formed in a first region of the semiconductor layer;   a second transparent electrode which is formed in a second region except for the first region of the semiconductor layer and which contains a metal atom;   a first electrode which is formed on the first transparent electrode and which is electrically connected with a part of the first transparent electrode; and   a second electrode which is formed on the second surface of the substrate,   wherein a contact resistance between the second transparent electrode and the semiconductor layer is 1×10 −4  Ω·cm 2  or less; and   wherein the metal atom is Ti, Au or Al.   
     
     
         2 . The semiconductor light-emitting element according to  claim 1 ,
 wherein each thickness of the first transparent electrode and the second transparent electrode is 0.1 μm to 10 μm.   
     
     
         3 . The semiconductor light-emitting element according to  claim 1 ,
 wherein a shape of the second transparent electrode when seen in a plane view is a shape which continuously surrounds a periphery of the first electrode, a shape which is obtained by arranging a plurality of circles so as to be separated from each other, or a shape obtained by arranging a plurality of polygons so as to be separated from each other.   
     
     
         4 . The semiconductor light-emitting element according to  claim 1 ,
 wherein a contact resistance between the first transparent electrode and the semiconductor layer is 1×10 −2  Ω·cm 2  to 5×10 −2  Ω·cm 2 .   
     
     
         5 . The semiconductor light-emitting element according to  claim 1 ,
 wherein an insulation film is formed in a region which is between the first transparent electrode and the semiconductor layer and which is overlapped with the first electrode when seen in a plane view.   
     
     
         6 . The semiconductor light-emitting element according to  claim 1 ,
 wherein the semiconductor layer is made of an AlGaAs-based material, an AlGaInAs-based material, an AlGaInP-based material, an AlGaInPAs-based material or an AlGaInN-based material.   
     
     
         7 . A method of manufacturing a semiconductor light-emitting element, comprising the steps of:
 (a) forming a semiconductor layer on a first surface of a substrate;   (b) forming a first transparent electrode on a first region of the semiconductor layer, and forming a second transparent electrode on a second region except for the first region of the semiconductor layer;   (c) forming a first electrode connected with a part of the first transparent electrode, on the first transparent electrode; and   (d) forming a second electrode on a second surface opposite to the first surface of the substrate,   the step of (b) further including the steps of:
 (b1) forming a third transparent electrode on the semiconductor layer; 
 (b2) forming a metal film on the third transparent electrode in the second region; and 
 (b3) performing a heat treatment after the step of (b2) so as to diffuse a metal atom from the metal film to the third transparent electrode in the second region, so that the second transparent electrode made of the third transparent electrode containing the metal atom is formed in the second region, and the first transparent electrode made of the third transparent electrode not containing the metal atom is formed in the first region, 
   wherein a contact resistance between the second transparent electrode and the semiconductor layer is 1×10 −4  Ω·cm 2  or less.   
     
     
         8 . The method of manufacturing the semiconductor light-emitting element according to  claim 7 ,
 wherein a concentration of the metal atom contained in the second transparent electrode is 1 wt % to 10 wt %.   
     
     
         9 . The method of manufacturing the semiconductor light-emitting element according to  claim 7 ,
 wherein a concentration of the metal atom contained in the second transparent electrode is 1 wt % to 3 wt %.   
     
     
         10 . The method of manufacturing the semiconductor light-emitting element according to  claim 7 ,
 wherein the metal atom is Ti, Au or Al.   
     
     
         11 . The method of manufacturing the semiconductor light-emitting element according to  claim 7 ,
 wherein a thickness of the third transparent electrode is 0.1 μm to 10 μm.   
     
     
         12 . The method of manufacturing the semiconductor light-emitting element according to  claim 7 ,
 wherein a shape of the second transparent electrode when seen in a plane view is a shape which continuously surrounds a periphery of the first electrode, a shape which is obtained by arranging a plurality of circles so as to be separated from each other, or a shape obtained by arranging a plurality of polygons so as to be separated from each other.   
     
     
         13 . The method of manufacturing the semiconductor light-emitting element according to  claim 7 ,
 wherein a contact resistance between the first transparent electrode and the semiconductor layer is 1×10 −2  Ω·cm 2  to 5×10 −2  Ω·cm 2 .   
     
     
         14 . The method of manufacturing the semiconductor light-emitting element according to  claim 7 , further comprising the step of, between the step of (a) and the step of (b):
 (e) forming an insulation film in a part or entire of the first region.   
     
     
         15 . The method of manufacturing the semiconductor light-emitting element according to  claim 7 ,
 wherein the semiconductor layer is made of an AlGaAs-based material, an AlGaInAs-based material, an AlGaInP-based material, an AlGaInPAs-based material or an AlGaInN-based material.