Light emitting diode having distributed bragg reflectors

Abstract

A light emitting diode (LED) having distributed Bragg reflector (DBR) and a manufacturing method thereof are provided. The distributed Bragg reflector is used as a reflective element for reflecting the light generated by the light emitting layer to an ideal direction of light output. The distributed Bragg reflector has a plurality of through holes, such that the metal layer and the transparent conductive layer disposed on two sides of the distributed Bragg reflector may contact each other to conduct the current. Due to the distribution properties of the through holes, the current may be more uniformly diffused, and the light may be more uniformly emitted from the light emitting layer.

What is claimed is: 
     
         1 . A light emitting diode, comprising:
 an epitaxial structure having a first type semiconductor layer, a second type semiconductor layer and a light emitting layer interposed therebetween;   a current blocking layer having blocking areas disposed on the epitaxial structure and exposing at least a portion of the second type semiconductor layer;   an ohmic contact layer disposed over the current blocking layer and electrically connected to the second type semiconductor layer;   a distributed Bragg reflector (DBR) layer disposed on the ohmic contact layer and having a plurality of first through holes formed therein, wherein each of the first through holes exposes a portion of the ohmic contact layer and is aligned with one of the blocking areas of the current blocking layer; and   a current conducting layer disposed on the DBR layer and electrically connected to the ohmic contact layer through the first through holes.   
     
     
         2 . The light emitting diode according to  claim 1 , wherein a plurality of second through holes are formed in the current blocking layer, each of the second through holes is aligned with a portion of the DBR layer. 
     
     
         3 . The light emitting diode according to  claim 1 , wherein the blocking areas of the current blocking layer are islands. 
     
     
         4 . The light emitting diode according to  claim 1 , further comprising:
 a first electrode electrically connected to the first semiconductor layer; and   a second disposed on the DBR layer and electrode electrically connected to the current conducting layer.   
     
     
         5 . The light emitting diode according to  claim 4 , further comprising:
 an insulating layer disposed over the current conducting layer and having at least one third through hole exposing a portion of the current conducting layer, wherein the second electrode is disposed on the insulating layer and electrically connected to the current conducting layer via the at least one third through hole.   
     
     
         6 . The light emitting diode according to  claim 5 , wherein a quantity of the at least one third through hole is two or more. 
     
     
         7 . The light emitting diode according to  claim 1 , wherein a plurality of intervals between the first through holes are unequal. 
     
     
         8 . The light emitting diode according to  claim 4 , wherein a plurality of intervals between the first through holes are unequal and the intervals gradually decrease along a direction away from the second electrode. 
     
     
         9 . A light emitting diode, comprising:
 an epitaxial structure having a first type semiconductor layer, a second type semiconductor layer and a light emitting layer interposed therebetween;   a current blocking layer having blocking areas disposed on the epitaxial structure and exposing at least a portion of the second type semiconductor layer;   an ohmic contact layer disposed over the current blocking layer and electrically connected to the second type semiconductor layer;   a distributed Bragg reflector (DBR) layer disposed on the ohmic contact layer and having a plurality of first through holes penetrating through the DBR layer and exposing portions of the ohmic contact layer, wherein each of the first through holes is aligned with one of the blocking areas of the current blocking layer; and   a first electrode disposed on the DBR layer and filled into the first through holes to be electrically connected to the ohmic contact layer.   The light emitting diode according to  claim 9 , wherein the ohmic contact layer comprises a transparent conductive layer.   
     
     
         10 . The light emitting diode according to  claim 9 , wherein a plurality of second through holes are formed in the current blocking layers, each of the second through holes is aligned with a portion of the DBR layer. 
     
     
         11 . The light emitting diode according to  claim 9 , wherein the blocking areas of the current blocking layer are islands. 
     
     
         12 . An light emitting diode, comprising:
 an epitaxial structure having a first type semiconductor layer, a second type semiconductor layer and a light emitting layer interposed therebetween;   a distributed Bragg reflector (DBR) layer disposed on the epitaxial structure and having a plurality of first through holes formed therein;   an interconnect layer disposed on the DBR layer and electrically connected to the second type semiconductor layer through the first through holes;   an insulating layer disposed over the interconnect layer and having at least one second through hole exposing a portion of the interconnect layer and each of at least the second through hole being aligned with a portion of the Bragg reflective layer; and   a first electrode disposed on the insulating layer and filled into the at least one second through hole to be electrically connected to the interconnect layer, wherein the at least one second through hole is aligned with a portion of the DBR layer.   
     
     
         13 . The light emitting diode according to  claim 12 , further comprising:
 an ohmic contact layer disposed between the interconnect layer and the second type semiconductor layer and electrically connecting the interconnect layer and the second type semiconductor layer.   
     
     
         14 . The light emitting diode according to  claim 12 , wherein a quantity of the at least one second through hole is two or more. 
     
     
         15 . The light emitting diode according to  claim 13 , wherein the ohmic contact layer comprises a transparent conductive layer. 
     
     
         16 . The light emitting diode according to  claim 12 , wherein the interconnect layer is in ohmic contact with the second type semiconductor layer. 
     
     
         17 . The light emitting diode according to  claim 12 , the further comprising:
 a current blocking layer having blocking areas disposed between the interconnect layer and the second type semiconductor layer.   
     
     
         18 . The light emitting diode according to  claim 17 , wherein a plurality of third through holes are formed in the current blocking layer, each of the second through holes is aligned with a portion of the DBR layer. 
     
     
         19 . The light emitting diode according to  claim 17 , wherein the blocking areas of the current blocking layer are islands. 
     
     
         20 . The light emitting diode according to  claim 12 , wherein a plurality of intervals between the first through holes are unequal and the intervals gradually decrease along a direction away from the first electrode.