Light-emitting device and method of manufacturing the same

Abstract

Provided is a light-emitting device and a method of manufacturing the same. The light-emitting device includes a substrate having at least one protruded portion with a curved surface in which a consistent defect density and uniform stress distribution can be obtained even when the growth of the semiconductor crystal layer and the forming of the light-emitting device are completed. In addition, the light-emitting device has a high the light extraction efficiency for extracting light generated at an electroluminescense layer externally.

1 . A light-emitting device comprising: 
 a substrate having at least one protruded portion with a curved surface, the crystal surface orientations of the at least one protruded portion are different from growth directions of a group III nitride compound semiconductor formed on the at least one protruded portion; and    a plurality of semiconductor crystal layers comprising a plurality of active layers and electrodes formed on a portion of the substrate.    
   
   
       2 . The device of  claim 1 , wherein curvatures at each point of the surface of the protruded portions is greater than 0.  
   
   
       3 . The device of  claim 2 , wherein each surface of the protruded portions has a different crystal orientation from a (0001) surface.  
   
   
       4 . The device of  claim 1 , wherein the protruded portions are hemispheres or stripes.  
   
   
       5 . The device of  claim 1 , wherein the substrate is composed of sapphire or material including Si.  
   
   
       6 . The device of  claim 1 , wherein an n-GaN layer is formed on the substrate, an active layer, a p-GaN layer, and a p-type electrode layer are formed sequentially on a portion of the n-GaN layer, and an n-type electrode layer is formed on a portion of the n-GaN layer where the active layer is not formed.  
   
   
       7 . A method of manufacturing a light-emitting device comprising: 
 forming at least one protruded portion with a curved surface on a planarized substrate; and    forming semiconductor crystal layers including active layers, on the substrate.    
   
   
       8 . The method of  claim 7  further comprising, before the forming the at least one protruded portion: 
 patterning a photo resist formed on the substrate;    hard baking the photo resist and the substrate; and    etching the surface of the substrate, thereby forming at least one protruded portion.    
   
   
       9 . The method of  claim 8 , wherein, when etching the substrate surface, an etching gas is a Cl gas selected from the group consisting of Cl 2 , BCl 3 , HCl, CCl 4 , and SiCl 4 .  
   
   
       10 . A method of manufacturing a light-emitting device comprising: 
 forming at least one protruded portion with a curved surface on a substrate; and    growing group III nitride compound semiconductor crystal layers from the substrate surface between the protruded portions until the surface of the protruded portions is covered.    
   
   
       11 . The method of  claim 10 , wherein each surface of the protruded portions has a different crystal direction from that of a (0001) surface.  
   
   
       12 . The method of  claim 10 , wherein the growing is epitaxial growing.