SUBSTRATE-FREE LIGHT EMITTING DIODE AND FABRICATION METHOD THEREOF

Abstract

A substrate-free light emitting diode (LED) including an epitaxy layer, a conductive supporting layer, and a first contact pad is provided. The epitaxy layer includes a first type doped semiconductor layer, a light emitting layer, and a second type doped semiconductor layer. The light emitting layer is disposed on the first type doped semiconductor layer, and a portion of the first type doped semiconductor layer is exposed. The second type doped semiconductor layer and the conductive supporting layer are sequentially disposed on the second type doped semiconductor layer. The first contact pad is disposed on the exposed first type doped semiconductor layer and electrically connected thereto. The first contact pad and the conductive supporting layer serving as an electrode are disposed on the same side of the epitaxy layer to avoid the light shielding effects of the electrode to improve the front light emitting efficiency of the LED.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a schematic cross-sectional view of a conventional LED.

FIGS. 2A and 2B are cross-sectional views illustrating the process of a conventional semiconductor element with a metal substrate.

FIGS. 3A-3F are cross-sectional views illustrating the process of the LED according to one preferred embodiment of the present invention.

Claims

1. A method for fabricating a substrate-free light emitting diode (LED), comprising: providing a template substrate;forming an epitaxy layer on the template substrate, wherein the epitaxy layer includes a first type doped semiconductor layer, a light emitting layer and a second type doped semiconductor layer sequentially stacked thereon;forming a metal layer on the epitaxy layer;removing the template substrate;removing portions of the metal layer, the second type doped semiconductor layer, and the light emitting layer to expose a part of the first type doped semiconductor layer, wherein the remaining metal layer forms a conductive supporting layer; andforming a first contact pad on the exposed first type doped semiconductor layer, wherein the first contact pad is electrically connected to the first type doped semiconductor layer.

2. The method for fabricating a substrate-free LED as claimed in claim 1, wherein a material of the template substrate comprises silicon, glass, GaAs, GaN, AlGaAs, GaP, SiC, InP, BN, Al2O3, sapphire or AlN.

3. The method for fabricating a substrate-free LED as claimed in claim 1, wherein the step for forming the first type doped semiconductor layer on the template substrate includes: forming a first contact layer on the template substrate; andforming a first cladding layer on the first contact layer.

4. The method for fabricating a substrate-free LED as claimed in claim 1, wherein the light emitting layer includes a Multiple Quantum Well (MQW) structure.

5. The method for fabricating a substrate-free LED as claimed in claim 1, wherein the step for forming the second type doped semiconductor layer includes: forming a second cladding layer on the light emitting layer; andforming a second contact layer on the second cladding layer.

6. The method for fabricating a substrate-free LED as claimed in claim 1, wherein the first type doped semiconductor layer and the second type doped semiconductor layer are an n-type semiconductor layer and a p-type semiconductor layer respectively.

7. The method for fabricating a substrate-free LED as claimed in claim 1, wherein the metal layer is formed through a plating process.

8. The method for fabricating a substrate-free LED as claimed in claim 7, wherein the plating process includes evaporation, sputtering, electroplating, or electroless-plating.

9. The method for fabricating a substrate-free LED as claimed in claim 8, wherein when the metal layer is formed by means of an electroplating process, an electroplating seed layer is first formed on the second type doped semiconductor layer, and then the metal layer is formed by means of the electroplating process.

10. The method for fabricating a substrate-free LED as claimed in claim 1, wherein the process of removing the template substrate includes a dry etching process, a wet etching process, a polishing process, or a lift-off process.

11. The method for fabricating a substrate-free LED as claimed in claim 1, wherein the process of removing the template substrate includes grinding and then polishing the template substrate.

12. The method for fabricating a substrate-free LED as claimed in claim 1, wherein the process of removing portions of the metal layer, the second type doped semiconductor layer and the light emitting layer includes a dry etching process or a wet etching process.

13. The method for fabricating a substrate-free LED as claimed in claim 1, wherein the step for removing portions of the metal layer, the second type doped semiconductor layer, and the light emitting layer further comprises a step of removing a part of the first type doped semiconductor layer to expose a part of the first type doped semiconductor layer.

14. The method for fabricating a substrate-free LED as claimed in claim 13, wherein the process of removing portions of the metal layer, the second type doped semiconductor layer, the light emitting layer, and the first type doped semiconductor layer includes a dry etching process or a wet etching process.

15. The method for fabricating a substrate-free LED as claimed in claim 1, further comprising a step of forming a second contact pad on the conductive supporting layer, wherein the second contact pad is electrically connected to the conductive supporting layer.

16. A substrate-free light emitting diode (LED), comprising: an epitaxy layer, comprising: a first type doped semiconductor layer;a light emitting layer, disposed on the first type doped semiconductor layer and exposing a portion of the first type doped semiconductor layer;a second type doped semiconductor layer, disposed on the light emitting layer;a conductive supporting layer, disposed on the second type doped semiconductor layer; anda first contact pad, disposed on the first type doped semiconductor layer exposed by the light emitting layer and electrically connected to the first type doped semiconductor layer.

17. The substrate-free LED as claimed in claim 16, wherein the first type doped semiconductor layer and the second type doped semiconductor layer are an n-type semiconductor layer and a p-type semiconductor layer respectively.

18. The substrate-free LED as claimed in claim 16, wherein the first type doped semiconductor layer comprises: a first contact layer; anda first cladding layer, disposed on the first contact layer.

19. The substrate-free LED as claimed in claim 16, wherein the light emitting layer includes a Multiple Quantum Well (MQW) structure.

20. The substrate-free LED as claimed in claim 16, wherein the second type doped semiconductor layer comprises: a second cladding layer, disposed on the light emitting layer; anda second contact layer, disposed on the second cladding layer.

21. The substrate-free LED as claimed in claim 16, wherein a material of the conductive supporting layer is selected from a group consisting of copper, nickel, gold, palladium, platinum, and alloys thereof.

22. The substrate-free LED as claimed in claim 16, further comprising a second contact pad disposed on the conductive supporting layer, wherein the second contact pad is electrically connected to the conductive supporting layer.

23. The substrate-free LED as claimed in claim 16, wherein a total thickness of the substrate-free LED is in a range of 11-120 μm.