LED device with embedded top electrode

• US 8,278,679 B2
• Filed: 09/22/2008
• Issued: 10/02/2012
• Est. Priority Date: 04/29/2008
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: TSMC Solid State Lighting Ltd. (Epistar Corporation)
• Inventors: Yu, Chen-Hua, Chen, Ding-Yuan, Chiou, Wen-Chih
• Primary Examiner(s): Wright, Tucker
• Application Number:
  US12/235,269
• Publication Number:
  US 20090267105A1
• Time in Patent Office: 1,471 Days
• Field of Search: 257 79-103, 257/E33.062, 257/E33.065
• US Class Current: 257/99
• CPC Class Codes: H01L 33/005 Processes
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials

Abstract

An LED device and a method of manufacturing, including an embedded top electrode, are presented. The LED device includes an LED structure and a top electrode. The LED structure includes layers disposed on a substrate, including an active light-emitting region. A top layer of the LED structure is a top contact layer. The top electrode is embedded into the top contact layer, wherein the top electrode electrically contacts the top contact layer.

Claims

1. A light emitting diode (LED) device comprising:

a substrate;

an LED structure having layers, including an active light-emitting layer, disposed on the substrate, and having a top contact epitaxial layer including a top surface; and

a first top electrode embedded into the top contact epitaxial layer such that a top surface of the first top electrode is recessed relative to the top surface of the top contact epitaxial layer without physically contacting the top contact epitaxial layer, wherein the first top electrode electrically contacts the top contact epitaxial layer.

2. The LED device of claim 1, wherein the first top electrode comprises a metal, a metal alloy, a conductive material, or combinations thereof.

3. The LED device of claim 1 further comprising:

a second top electrode; and

a conductive web connecting the first top electrode and the second top electrode.

4. The LED device of claim 3, wherein the conductive web comprises a metal, a metal alloy, a conductive material, or combinations thereof.

5. The LED device of claim 3, wherein the conductive web extends less than about 50 nm into the top contact layer.

6. The LED device of claim 1, wherein the first top electrode is recessed from a top plane of the top contact epitaxial layer.

7. The LED device of claim 6 further comprising:

a non-conductive layer beneath the first top electrode.

8. The LED device of claim 1, wherein the first top electrode extends greater than about 50 nm and less than about 150 nm into the top contact layer.

9. The LED device of claim 1, wherein the first top electrode has a non-conductive bottom surface.

10. A light emitting diode (LED) structure comprising:

a top contact layer; and

an electrode embedded in the top contact layer, the electrode having a total surface area comprising a contacting surface area of Ac and a remaining surface area of Ar, wherein Ac>

Ar, wherein the electrode has a non-conductive bottommost surface.

11. The LED structure of claim 10, wherein Ac>

1.5Ar.

12. The LED structure of claim 10, wherein the top contact layer is a doped semiconductor layer.

13. The LED structure of claim 10, wherein the electrode comprises a metal, a metal alloy, a conductive material, or combinations thereof.

14. The LED structure of claim 10, wherein the entire electrode is below a top surface of the top contact layer.

15. The LED structure of claim 10, wherein the non-conductive bottommost surface is embedded deeper into the top contact layer than any other portion of the electrode.

16. An LED device comprising:

a substrate comprising LED structure layers, including an active light-emitting layer, the LED structure layers having a top contact layer;

an opening in the top contact layer defined by an upper surface of the top contact layer; and

a first conductive layer, at least partially filling the opening in the top contact layer, thereby forming a top electrode, wherein the top electrode is in electrical contact with the top contact layer, wherein the top electrode has an upper surface that is below the upper surface of the top contact layer without physically contacting the top contact layer.

17. The LED device of claim 16, wherein the top electrode comprises a metal, a metal alloy, a conductive material, or combinations thereof.

18. The LED device of claim 16 further comprising a conductive web on the top contact layer, wherein the conductive web contacts the top contact layer.

19. The LED device of claim 18 wherein the conductive web and the top electrode are comprised of the same conductive material.

20. The LED device of claim 18, wherein the conductive web contacts the top contact layer and a plurality of top electrodes.