Gallium nitride based compound semiconductor light-emitting device having high emission efficiency and method of manufacturing the same

Abstract

The present invention provides a gallium nitride based compound semiconductor light-emitting device having high light emission efficiency and a low driving voltage Vf. The gallium nitride based compound semiconductor light-emitting device includes a p-type semiconductor layer, and a transparent conductive oxide film that includes dopants and is formed on the p-type semiconductor layer. A dopant concentration at an interface between the p-type semiconductor layer and the transparent conductive oxide film is higher than the bulk dopant concentration of the transparent conductive oxide film. Therefore, the contact resistance between the p-type semiconductor layer and the transparent conductive oxide film is reduced.

1 . A method of manufacturing a gallium nitride based compound semiconductor light-emitting device, the method comprising:
 forming a transparent conductive oxide film including dopants on a p-type semiconductor layer of a gallium nitride based compound semiconductor device; and   performing a thermal annealing process at a temperature higher than 300° C.   
     
     
         2 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 1 , wherein performing the thermal annealing process comprises:
 performing the thermal annealing process at a temperature in the range of 300° C. to 900° C.   
     
     
         3 . A method of manufacturing a gallium nitride based compound semiconductor light-emitting device, the method comprising:
 forming a transparent conductive oxide film including dopants on a p-type semiconductor layer of a gallium nitride based compound semiconductor device; and   performing a laser annealing process using an excimer laser.   
     
     
         4 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 1 ,
 wherein, before the transparent conductive oxide film including the dopants is formed on the p-type semiconductor layer, an uneven surface is formed on at least a portion of the p-type semiconductor layer.   
     
     
         5 . A method of manufacturing a gallium nitride based compound semiconductor light-emitting device, the method comprising:
 sequentially forming a highly doped layer and a transparent conductive oxide film on a p-type semiconductor layer of a gallium nitride based compound semiconductor device; and   performing a thermal annealing process at a temperature higher than 300° C.   
     
     
         6 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 5 , wherein performing the thermal annealing process comprises:
 performing a thermal annealing process at a temperature in the range of 300° C. to 900° C.   
     
     
         7 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 5 ,
 wherein, before the highly doped layer and the transparent conductive oxide film are sequentially formed on the p-type semiconductor layer, an uneven surface is formed on at least a portion of the p-type semiconductor layer.   
     
     
         8 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 6 ,
 wherein, before the highly doped layer and the transparent conductive oxide film are sequentially formed on the p-type semiconductor layer, an uneven surface is formed on at least a portion of the p-type semiconductor layer.   
     
     
         9 . A method of manufacturing a gallium nitride based compound semiconductor light-emitting device in which an uneven surface is formed on at least a portion of a p-type semiconductor layer of a gallium nitride based compound semiconductor device and a transparent conductive oxide film having a high dopant concentration is formed on the p-type semiconductor layer, the method comprising:
 (1) a process of sequentially forming on a substrate an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer, each composed of a gallium nitride based compound semiconductor;   (2) a process of forming a mask made of metal particles on the p-type semiconductor layer; and   (3) a process of performing dry etching on the p-type semiconductor layer using the mask.   
     
     
         10 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 9 ,
 wherein the process (2) includes:   forming a metal thin film on the p-type semiconductor layer; and   performing a heat treatment.   
     
     
         11 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 9 ,
 wherein the metal particles of the mask are made of Ni, or Ni alloy.   
     
     
         12 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 10 ,
 wherein the metal particles of the mask are made of Ni, or Ni alloy.   
     
     
         13 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 9 ,
 wherein the metal particles of the mask are made of a metal with a low melting point or an alloy metal with a low melting point having a melting point in the range of 100° C. to 450° C.   
     
     
         14 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 9 ,
 wherein the metal particles of the mask are made of a metal with a low melting point selected from Ni, Au, Sn, Ge, Pb, Sb, Bi, Cd, and In, or an alloy metal with a low melting point including at least one of the metallic materials.   
     
     
         15 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 9 ,
 wherein the uneven surface is formed on at least a portion of the p-type semiconductor layer by wet etching.   
     
     
         16 . The method of manufacturing a gallium nitride based compound semiconductor light-emitting device according to  claim 1 , wherein
 the thermal annealing process is performed after forming a transparent conductive oxide film.