Light-emitting diode structure and method for manufacturing the same

Abstract

A light-emitting diode (LED) structure and a method for manufacturing the LED structure are disclosed for promoting the recognition rate of LED chips, wherein a roughness degree of the surface under a first electrode pad of a first conductivity type is made similar to that of the surface under a second electrode pad of a second conductivity type, so that the luster shown from the first electrode pad can be similar to that from the second electrode pad, thus resolving the poor recognition problem of wire-bonding machines caused by different lusters from the first and second electrode pads.

1 . A light-emitting diode (LED) structure comprising:
 a substrate;   a first confining layer having a first electrical property, wherein the first confining layer is disposed on the substrate;   a light-emitting epitaxial structure disposed on a first portion of the first confining layer, wherein the light-emitting epitaxial structure comprises;
 an active layer disposed on the first portion of the confining layer; and 
 a second confining layer having a second electrical property, wherein the second confining layer is disposed on the active layer, and the first electrical property is opposite to the second electrical property; 
   a protrusive structure disposed on a second portion of the first confining layer, wherein the protrusive structure is spaced from the light-emitting epitaxial structure by a predetermined gap exposing the first confining layer, and the material layers forming the protrusive structure are substantially equivalent to the material layers forming the light-emitting epitaxial structure with respect to material species and arrangement sequence, and a thickness of the material layers forming the protrusive structure is smaller than or equal to a thickness of the material layers forming the light-emitting epitaxial structure;   a n-type electrode pad covering the protrusive structure, wherein the n-type electrode pad is electrically connected to the first confining layer; and   a p-type electrode pad disposed on the second confining layer.   
   
   
       2 . The light-emitting diode structure according to  claim 1 , further comprising:
 a buffer layer disposed between the substrate and the first confining layer.   
   
   
       3 . The light-emitting diode structure according to  claim 2 , wherein the buffer layer further comprises:
 a low-temperature buffer layer disposed on the substrate; and   a high-temperature buffer layer disposed on the low-temperature buffer layer.   
   
   
       4 . The light-emitting diode structure according to  claim 1 , wherein the material forming the substrate is selected from the group consisting of sapphire, ZnO, LiGaO 2 , spinel, SiC, GaN and silicon. 
   
   
       5 . The light-emitting diode structure according to  claim 1 , wherein the first electrical property is n type, and the second electrical property is p type. 
   
   
       6 . The light-emitting diode structure according to  claim 1 , wherein the protrusive structure is composed of a plurality of protrusive structure units. 
   
   
       7 . The light-emitting diode structure according to  claim 1 , further comprising:
 a transparent electrode layer disposed on a top surface of the light-emitting epitaxial structure, wherein the p-type electrode pad is disposed on the transparent electrode layer.   
   
   
       8 . The light-emitting diode structure according to  claim 1 , further comprising
 a transparent electrode layer disposed on a top surface of the protrusive structure, wherein the n-type electrode pad covers the protrusive structure and the transparent electrode layer.   
   
   
       9 . A method for manufacturing a light-emitting diode structure, comprising:
 providing a substrate;   forming a first confining layer having a first electrical property on the substrate;   forming an active layer on the confining layer;   forming a second confining layer having a second electrical property on the active layer, wherein the first electrical property is opposite to the second electrical property;   coating a photoresist layer on a surface of the second confining layer, wherein the photoresist layer has a predetermined gap;   etching the second confining layer and the active layer along the predetermined gap by using the photoresist layer as a mask;   removing the photoresist layer, thereby forming a light-emitting epitaxial structure and a protrusive structure;   fabricating a n-type electrode pad covering the protrusive structure, wherein the n-type electrode pad is electrically connected to the first confining layer; and   fabricating a p-type electrode pad on a top surface of the light-emitting epitaxial structure.   
   
   
       10 . The method according to  claim 9 , further comprising:
 forming a buffer layer between the substrate and the first confining layer.   
   
   
       11 . The method according to  claim 9 , further comprising:
 respectively forming a low-temperature buffer layer and a high-temperature buffer layer between the substrate and the first confining layer, wherein the low-temperature buffer layer is disposed on the substrate, and the high-temperature buffer layer is disposed on the low-temperature buffer layer.   
   
   
       12 . The method according to  claim 9 , wherein the material forming the substrate is selected from the group consisting of sapphire, ZnO, LiGaO 2 , spinel, SiC, GaN and silicon. 
   
   
       13 . The method according to  claim 9 , wherein the first electrical property is n type, and the second electrical property is p type. 
   
   
       14 . The method according to  claim 9 , wherein the protrusive structure is composed of a plurality of protrusive structure units. 
   
   
       15 . The method according to  claim 9 , further comprising:
 forming a transparent electrode layer on a top surface of the light-emitting epitaxial structure; and   forming the p-type electrode pad on the transparent electrode layer.   
   
   
       16 . The method according to  claim 9 , further comprising:
 forming a transparent electrode layer on a top surface of the protrusive structure; and   forming the n-type electrode pad covering the protrusive structure and the transparent electrode layer.