Light emitting diode

Abstract

A light emitting diode including a lower semiconductor layer formed on a substrate; an upper semiconductor layer disposed above the lower semiconductor layer, exposing an edge region of the lower semiconductor layer; a first electrode formed on the upper semiconductor layer; an insulation layer interposed between the first electrode and the upper semiconductor layer, to supply electric current to the lower semiconductor layer; a second electrode formed on another region of the upper semiconductor layer, to supply electric current to the upper semiconductor layer. The first electrode includes an electrode pad disposed on the upper semiconductor layer and an extension extending from the electrode pad to the exposed lower semiconductor layer. The insulation layer may have a distributed Bragg reflector structure.

What is claimed is: 
     
         1 . A light emitting diode, comprising:
 a substrate;   a lower semiconductor layer disposed on the substrate;   an upper semiconductor layer disposed on the lower semiconductor layer, such than a portion of the lower semiconductor layer is exposed;   a first electrode disposed on the upper semiconductor layer and the exposed portion of the lower semiconductor layer, to supply electric current to the lower semiconductor layer;   a first insulation layer disposed between the first electrode and the upper semiconductor layer; and   a second electrode formed on the upper semiconductor layer, to supply electric current to the upper semiconductor layer.   
     
     
         2 . The light emitting diode of  claim 1 , wherein the first insulation layer directly contacts surfaces of the upper semiconductor layer. 
     
     
         3 . The light emitting diode of  claim 1 , further comprising: a second insulation layer having a distributed Bragg reflector (DBR) structure, disposed between the first electrode and the first insulation layer, the second insulation layer contacting the exposed portion of the lower semiconductor layer. 
     
     
         4 . The light emitting diode of  claim 1 , further comprising: a second insulation layer having a distributed Bragg reflector (DBR) structure, disposed under the second electrode. 
     
     
         5 . The light emitting diode of  claim 1 , wherein the second electrode comprises:
 a second electrode pad disposed on the upper semiconductor layer; and   a second extension that extends from the second electrode pad, across the upper semiconductor layer.   
     
     
         6 . The light emitting diode of  claim 1 , further comprising a lower insulation layer having a distributed Bragg reflector (DBR) structure, disposed on the substrate. 
     
     
         7 . The light emitting diode of  claim 6 , wherein the lower insulation layer is disposed on process-induced strain silicon (PSS) regions of the substrate. 
     
     
         8 . The light emitting diode of  claim 6 , wherein the lower insulation layer is disposed on the bottom surface of the substrate. 
     
     
         9 . The light emitting diode of  claim 1 , further comprising a transparent electrode layer disposed on the upper semiconductor layer. 
     
     
         10 . The light emitting diode of  claim 1 , wherein the first insulation layer comprises:
 first layers comprising silicon, having a first index of refraction; and   second layers having a second index of refraction that is different from the first index of refraction,   wherein the first layers and the second layers are alternately stacked upon one another, starting and ending with ones of the first layers.   
     
     
         11 . The light emitting diode of  claim 3 , wherein the second insulation layer comprises:
 first layers comprising silicon, having a first index of refraction; and   second layers having a second index of refraction that is different from the first index of refraction, wherein,   the first layers and the second layers are alternately stacked upon one another, starting and ending with ones of the first layers.   
     
     
         12 . The light emitting diode of  claim 4 , wherein the second insulation layer comprises:
 first layers comprising silicon, having a first index of refraction; and   
       second layers having a second index of refraction that is different from the first index of refraction, wherein,
 the first layers and the second layers are alternately stacked upon one another, starting and ending with ones of the first layers. 
 
     
     
         13 . The light emitting diode of  claim 6 , wherein the lower insulation layer comprises:
 first layers comprising silicon, having a first index of refraction; and   second layers having a second index of refraction that is different from the first index of refraction, wherein,   the first layers and the second layers are alternately stacked upon one another, starting and ending with ones of the first layers.   
     
     
         14 . A light emitting diode, comprising:
 a substrate;   a light emitting unit disposed on the substrate, comprising:   a lower semiconductor layer disposed on the substrate;   an active layer disposed on the lower semiconductor layer, such than a portion of the lower semiconductor layer is exposed;   an upper semiconductor layer disposed on the active layer;   a first electrode to supply electric current to the lower semiconductor layer, comprising:   a first electrode pad disposed on the upper semiconductor layer;   a lower extension that extends along the exposed portion of the lower semiconductor layer; and   an inclined extension that extends from the first electrode pad to the lower extension, along edges of the upper semiconductor layer, active layer, and lower semiconductor layer;   a first insulation layer disposed between the first electrode pad and the inclined extension, and the light emitting unit;   a reflective second insulation layer disposed between the first insulation layer and the first electrode;   a second electrode formed on the upper semiconductor layer, to supply electric current to the upper semiconductor layer.   
     
     
         15 . The light emitting diode of  claim 14 , wherein the second insulation comprises layers having different indices of reflection that are stacked on one another, such that the second insulation layer has a distributed Bragg reflector (DBR) structure, wherein top and bottom ones of the stacked layers comprise silicon. 
     
     
         16 . The light emitting diode of  claim 14 , wherein the exposed portion of the lower semiconductor layer is thinner than portions of the lower semiconductor layer upon which the active layer is disposed.