Light Emitting Diode Structure

Abstract

A light emitting diode structure includes a first type semiconductor layer, a second type semiconductor layer, an active layer disposed therebetween, and a reflective stacked layer. The reflective stacked layer includes a first reflective layer and a second reflective layer. The first reflective layer is disposed at a side of the second type semiconductor layer opposing the active layer. The second reflective layer is disposed at a side of the first reflective layer opposing the second type semiconductor layer, and extends along a side surface of the first reflective layer to a surface of the second type semiconductor layer. A vertical projection area of the second reflective layer on the second-type semiconductor layer is greater than that of the first reflective layer thereon. The second reflective layer has a better resistance to migration than the first reflective layer.

What is claimed is: 
     
         1 . A light emitting diode structure, comprising:
 a first type semiconductor layer;   an active layer;   a second type semiconductor layer, wherein the active layer is disposed between the first type semiconductor layer and the second type semiconductor layer; and   a reflective stacked layer, comprising:
 a first reflective layer disposed at a side of the second type semiconductor layer opposing the active layer; and 
 a second reflective layer which is disposed at a side of the first reflective layer opposing the second type semiconductor layer, and extends along a side surface of the first reflective layer to a surface of the second type semiconductor layer, 
 wherein the first reflective layer has a first surface proximate to the second type semiconductor layer, and the second reflective layer has a second surface proximate to the second type semiconductor layer, and a vertical projection area of the second reflective layer on the second type semiconductor layer is greater than a vertical projection area of the first reflective layer on the second type semiconductor layer, and the second reflective layer has a better resistance to migration than the first reflective layer. 
   
     
     
         2 . The light emitting diode structure of  claim 1 , wherein a reflectance of the first reflective layer is greater than a reflectance of the second reflective layer. 
     
     
         3 . The light emitting diode structure of  claim 2 , wherein the reflectance of the first reflective layer is in a range substantially from 90% to 100%, and the reflectance of the second reflective layer is substantially greater than 80% but smaller than the reflectance of the first reflective layer. 
     
     
         4 . The light emitting diode structure of  claim 1 , wherein the first surface and the second surface form a reflective surface of the reflective stacked layer. 
     
     
         5 . The light emitting diode structure of  claim 4 , wherein the first surface substantially occupies 80% to 99% of an area of the reflective surface, and the second surface substantially occupies 1% to 20% of the area of the reflective surface. 
     
     
         6 . The light emitting diode structure of  claim 4 , wherein the first surface substantially occupies 90% to 95% of an area of the reflective surface, and the second surface substantially occupies 5% to 10% of the area of the reflective surface. 
     
     
         7 . The light emitting diode structure of  claim 4 , wherein the reflective stacked layer comprises a first blocking layer disposed between the first reflective layer and the second reflective layer. 
     
     
         8 . The light emitting diode structure of  claim 7 , wherein the reflective stacked layer comprises a second blocking layer disposed at a side of the second reflective layer opposing the first reflective layer. 
     
     
         9 . The light emitting diode structure of  claim 8 , further comprising a current blocking layer, wherein the second reflective layer further comprises a recess disposed at a side of the second reflective layer facing the second type semiconductor layer, and the current blocking layer is disposed in the recess and adjoins the second type semiconductor layer. 
     
     
         10 . The light emitting diode structure of  claim 1 , wherein a projection of the first reflective layer on the second type semiconductor layer is located in a projection of the second reflective layer on the second type semiconductor layer. 
     
     
         11 . The light emitting diode structure of  claim 1 , wherein the first reflective layer is formed from silver, and the second reflective layer is formed from aluminum, rhodium, a silver alloy, or a combination thereof. 
     
     
         12 . The light emitting diode structure of  claim 1 , wherein the first reflective layer is formed from silver or a silver alloy, and the second reflective layer is formed from aluminum, rhodium, or a combination thereof. 
     
     
         13 . The light emitting diode structure of  claim 1 , further comprising a transparent conductive layer disposed between the second type semiconductor layer and the reflective stacked layer. 
     
     
         14 . The light emitting diode structure of  claim 1 , wherein the reflective stacked layer further comprises a transparent conductive layer disposed between the first reflective layer and the second type semiconductor layer, and a surface of the transparent conductive layer facing the second type semiconductor layer and the second surface are coplanar to form a reflective surface of the reflective stacked layer. 
     
     
         15 . The light emitting diode structure of  claim 14 , wherein a reflectance of the first reflective layer is greater than a reflectance of the second reflective layer. 
     
     
         16 . The light emitting diode structure of  claim 15 , wherein the reflectance of the first reflective layer is in a range substantially from 90% to 100%, and the reflectance of the second reflective layer is substantially greater than 80% but smaller than the reflectance of the first reflective layer. 
     
     
         17 . The light emitting diode structure of  claim 15 , wherein the surface of the transparent conductive layer facing the second type semiconductor layer substantially occupies 80% to 99% of an area of the reflective surface, and the second surface substantially occupies 1% to 20% of the area of the reflective surface. 
     
     
         18 . The light emitting diode structure of  claim 13 , wherein the reflective stacked layer comprises a first blocking layer disposed between the first reflective layer and the second reflective layer. 
     
     
         19 . The light emitting diode structure of  claim 18 , wherein the reflective stacked layer comprises a second blocking layer disposed at a side of the second reflective layer opposing the first reflective layer. 
     
     
         20 . The light emitting diode structure of  claim 19 , further comprising a current blocking layer, wherein the second reflective layer further comprises a recess disposed at a side of the second reflective layer facing the second type semiconductor layer, and the current blocking layer is disposed in the recess and adjoins the second type semiconductor layer.