Method of fabricating vertical structure nitride semiconductor light emitting device

Abstract

A method of fabricating a vertical structure nitride semiconductor light emitting device having a cross-sectional shape of a polygon having five or more sides or a circle. A light emitting structure is formed on a sapphire substrate. A metal layer having a plurality of patterns is formed on the light emitting structure. The patterns of the metal layer each have a shape corresponding to a cross-sectional shape of a wanted final light emitting device and are spaced apart by a predetermined distance such that an upper surface of the light emitting structure is partially exposed. The light emitting structure is divided into a plurality of individualized light emitting structures by removing the light emitting structure below the exposed region between the patterns of the metal layer. The sapphire substrate is separated from the light emitting structure by irradiating a laser beam.

1 . A method of fabricating a vertical structure nitride semiconductor light emitting device, the method comprising: 
 forming a light emitting structure including an n-type nitride semiconductor layer, an active layer and a p-type nitride semiconductor layer sequentially disposed on a sapphire substrate;    forming a metal layer having a plurality of patterns on the light emitting structure, the plurality of patterns of the metal layer each having a shape corresponding to a cross-sectional shape of a wanted final light emitting device and being spaced apart by a predetermined distance such that an upper surface of the light emitting structure is partially exposed;    dividing the light emitting structure into a plurality of individualized light emitting structures each having a size corresponding to a size of the final light emitting device by removing the light emitting structure below the exposed region between the plurality of patterns of the metal layer;    separating the sapphire substrate from the light emitting structure by irradiating a laser beam onto a lower surface of the sapphire substrate, whereby the light emitting structure is completely separated in the size corresponding to the size of the final light emitting device; and    forming a bonding pad on a surface of the n-type nitride semiconductor layer from which the sapphire substrate is removed.    
   
   
       2 . The method of  claim 1 , wherein the forming of the metal layer having the plurality of patterns, comprises: 
 forming a mask pattern which exposes predetermined regions of an upper surface of the light emitting structure on which the plurality of patterns of the metal layer are formed, but covers remaining regions other than the predetermined regions of the upper surface of the light emitting structure;    forming a metal layer on the exposed regions of the upper surface of the light emitting structure using a plating method; and    removing the mask pattern.    
   
   
       3 . The method of  claim 1 , wherein the plurality of patterns of the metal layer have a polygonal cross section having five or more sides.  
   
   
       4 . The method of  claim 1 , wherein the plurality of pattern of the metal layer have a circular cross section.  
   
   
       5 . The method of  claim 1 , wherein the separating of the light emitting structure comprises removing the light emitting structure corresponding to the exposed regions between the plurality of patterns of the metal layer using a dry etching method.  
   
   
       6 . The method of  claim 1 , wherein the separating of the sapphire substrate comprises irradiating the laser beam at least two times onto the lower surface of the sapphire substrate located below the individualized light emitting structures divided in the size of the final light emitting device.  
   
   
       7 . The method of  claim 1 , wherein the forming of the light emitting structure further comprises forming a high reflective ohmic contact layer having a conductivity and a reflectivity on the p-type nitride semiconductor layer.  
   
   
       8 . The method of  claim 7 , wherein the high reflective ohmic contact layer comprises at least one layer made of one selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf and a combination thereof.  
   
   
       9 . The method of  claim 1 , wherein the forming of the bonding pad comprises: 
 forming a transparent electrode layer on a surface of the n-type nitride semiconductor layer from which the sapphire substrate is removed; and    forming the bonding pad on a lower surface of the transparent electrode layer.    
   
   
       10 . The method of  claim 9 , wherein the transparent electrode layer is formed in at least one layer of one selected from Indium tin oxide (ITO), indium oxide (IO), Tin dioxide (SnO 2 ) and indium zinc oxide (IZO).  
   
   
       11 . A method of fabricating a vertical structure nitride semiconductor light emitting device, the method comprising: 
 forming a light emitting structure including an n-type nitride semiconductor layer, an active layer and a p-type nitride semiconductor layer sequentially disposed on a sapphire substrate;    dividing the light emitting structure into a plurality of individualized light emitting structures each having a cross section and a size of a wanted final light emitting device by partially removing the light emitting structure;    forming a metal layer on upper surfaces of the individualized light emitting structures;    separating the sapphire substrate from the individualized light emitting structures by irradiating a laser beam onto a lower surface of the sapphire substrate, whereby the individualized light emitting structures are completely separated in the size of the final light emitting device; and    forming a bonding pad on a surface of the n-type nitride semiconductor layer from which the sapphire substrate is removed.    
   
   
       12 . The method of  claim 11 , wherein the separating of the light emitting device into the plurality of individualized light emitting devices, comprises: 
 forming a mask pattern which exposes predetermined regions of an upper surface of the light emitting structure corresponding to upper surfaces of the plurality of individualized light emitting structures, but covers remaining regions other than the predetermined regions of the upper surface of the light emitting structure; and    removing the exposed regions of the upper surface of the light emitting device using a dry etch method.    
   
   
       13 . The method of  claim 11 , wherein the final light emitting device has a polygonal cross section having five or more sides.  
   
   
       14 . The method of  claim 1 , wherein the final light emitting device has a circular cross section.  
   
   
       15 . The method of  claim 11 , wherein the forming of the metal layer comprises: 
 forming a mask pattern higher than the individualized light emitting structures between the plurality of individualized light emitting structures;    forming a metal layer on the individualized light emitting structures using a plating method; and    removing the mask pattern.    
   
   
       16 . The method of  claim 11 , wherein the separating of the sapphire substrate comprises irradiating the laser beam at least two times onto the lower surface of the sapphire substrate located below the individualized light emitting structures.  
   
   
       17 . The method of  claim 11 , wherein the forming of the light emitting structure further comprises forming a high reflective ohmic contact layer having a conductivity and a reflectivity on the p-type nitride semiconductor layer.  
   
   
       18 . The method of  claim 17 , wherein the high reflective ohmic contact layer comprises at least one layer made of one selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf and a combination thereof.  
   
   
       19 . The method of  claim 11 , wherein the forming of the bonding pad comprises: 
 forming a transparent electrode layer on a surface of the n-type nitride semiconductor layer from which the sapphire substrate is removed; and    forming the bonding pad on a lower surface of the transparent electrode layer.    
   
   
       20 . The method of  claim 19 , wherein the transparent electrode layer is formed in at least one layer of one selected from Indium tin oxide (ITO), indium oxide (IO), Tin dioxide (SnO 2 ) and indium zinc oxide (IZO).