Light emitting device and method of forming the same

Abstract

A light-emitting device includes a transparent substrate, a transparent adhesive layer on the transparent substrate, a first transparent conductive layer on the transparent adhesive layer, a multi-layer epitaxial structure and a first electrode on the transparent conductive layer, and a second electrode on the multi-layer epitaxial structure. The multi-layer epitaxial structure includes a light-emitting layer. The transparent substrate has a first surface facing the transparent adhesive layer and a second surface opposite to the first surface, wherein the area of the second surface is larger than that of the light-emitting layer, and the area ratio thereof is not less than 1.6.

1 . A light-emitting device, comprising:
 a transparent substrate;   a transparent adhesive layer on said transparent substrate;   a multi-layer epitaxial structure on said transparent adhesive layer, and said multi-layer epitaxial structure comprising a light-emitting layer;   a first electrode on said transparent adhesive layer; and   a second electrode on said multi-layer epitaxial structure;   wherein said transparent substrate has a first surface facing said transparent adhesive layer and a second surface opposite to said first surface, the ratio of the area of said second surface to the area of said light-emitting layer is not less than 1.6.   
   
   
       2 . The light-emitting device according to  claim 1 , further comprising a reflective layer on said second surface. 
   
   
       3 . The light-emitting device according to  claim 1 , wherein the area of said second surface is larger than the area of said first surface. 
   
   
       4 . The light-emitting device according to  claim 1 , wherein the ratio of the area of said second surface to the area of said first surface ranges between 4 and 20. 
   
   
       5 . The light-emitting device according to  claim 1 , wherein said first surface further comprises an exposed portion not covered with said light-emitting layer. 
   
   
       6 . The light-emitting device according to  claim 1 , further comprising a first transparent conductive layer on said transparent adhesive layer. 
   
   
       7 . The light-emitting device according to  claim 6 , wherein said first transparent conductive layer is selected from a group consisting of indium tin oxide, cadmium tin oxide, zinc oxide, and zinc tin oxide. 
   
   
       8 . The light-emitting device according to  claim 1 , further comprising a second transparent conductive layer between said second electrode and said multi-layer epitaxial structure. 
   
   
       9 . The light-emitting device according to  claim 8 , wherein said second transparent conductive layer is selected from a group consisting of indium tin oxide, cadmium tin oxide, zinc oxide, and zinc tin oxide. 
   
   
       10 . The light-emitting device according to  claim 1 , wherein said multi-layer epitaxial structure comprises a contact layer and a confinement layer. 
   
   
       11 . The light-emitting device according to  claim 10 , wherein said contact layer is selected from a group consisting of GaP, GaAs, and GaAsP. 
   
   
       12 . The light-emitting device according to  claim 1 , wherein said transparent adhesive layer is selected from a group consisting of spin-on glass, silicone, Benzocyclobutene(BCB), Epoxy, polyimide, and Perfluorocyclobutane(PFCB). 
   
   
       13 . A method of forming a light-emitting device, comprising:
 providing a temporary substrate having a multi-layer epitaxial structure and a first transparent conductive layer thereon;   cutting said temporary substrate to form a first dice comprising a portion of each of said multi-layer epitaxial structure, said first transparent conductive layer, and said temporary substrate;   providing a transparent substrate having a transparent adhesive layer on said transparent substrate;   attaching said first dice to said transparent adhesive layer; and   cutting said transparent substrate to form a second dice comprising said first dice, a portion of each of said transparent adhesive layer and said transparent substrate,   wherein said transparent substrate of said second dice has a first surface facing said transparent adhesive layer and a second surface opposite to said first surface, the ratio of the area of said second surface to the area of a light-emitting layer of said second dice is not less than 1.6.   
   
   
       14 . The method according to  claim 13 , further comprising removing said temporary substrate of said first dice after attaching said first dice on said transparent adhesive layer. 
   
   
       15 . The method according to  claim 14 , after removing said temporary substrate of said first dice, further comprising:
 etching a portion of said multi-layer epitaxial structure of said first dice to expose said first transparent conductive layer;   forming a first electrode on said exposed first transparent conductive layer; and   forming a second electrode on said multi-layer epitaxial structure of said first dice.   
   
   
       16 . The method according to  claim 13 , after said step of attaching said first dice to said transparent adhesive layer, further comprising removing said transparent adhesive layer not covered with said first dice. 
   
   
       17 . The method according to  claim 13 , further comprising providing a reflective layer on said second surface. 
   
   
       18 . The method according to  claim 13 , wherein said cutting step is performed by use of a diamond tool or a laser tool. 
   
   
       19 . The method according to  claim 13 , wherein the area of said second surface is larger than the area of said first surface. 
   
   
       20 . The method according to  claim 13 , wherein the ratio of the area of said second surface to the area of said first surface ranges between 4 and 20. 
   
   
       21 . The method according to  claim 15 , further comprising a step of forming a second transparent conductive layer between said second electrode and said multi-layer epitaxial structure of said first dice. 
   
   
       22 . A method of forming a light-emitting device, comprising:
 providing a transparent substrate having a light-emitting element thereon, said light-emitting element comprising a transparent adhesive layer on said transparent substrate, a multi-layer epitaxial structure on said transparent adhesive layer, a first electrode on said transparent adhesive layer, and a second electrode on said multi-layer epitaxial structure; and   cutting said transparent substrate to make the ratio of the area of a second surface of said transparent substrate, distant from said transparent adhesive layer, to the area of a light-emitting layer of said multi-layer epitaxial structure is not less than 1.6.   
   
   
       23 . The method according to claim  28 , further comprising providing a reflective layer on said second surface. 
   
   
       24 . The method according to claim  28 , wherein said cutting step is performed by use of a diamond tool or a laser tool. 
   
   
       25 . The method according to claim  28 , wherein said transparent substrate comprises a first surface opposite to said second surface, the ratio of the area of said second surface to the area of said first surface ranges between 4 and 20. 
   
   
       26 . The method according to claim  35 , wherein said first surface further comprises an exposed portion not covered with said light-emitting layer.