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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B are schematic diagrams of conventional light emitting diodes;

FIGS. 2A-2C are schematic diagrams of light emitting devices according to the present invention;

FIGS. 3-6 are schematic diagrams showing the steps of forming a light emitting devices according to the present invention; and

FIGS. 7A-7C are schematic diagrams showing different cutting methods implemented in the present invention.

Claims

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; anda 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; andcutting 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; andforming 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; andcutting 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.