Electrode structure of light emitting device

• US 9,893,257 B2
• Filed: 11/21/2016
• Issued: 02/13/2018
• Est. Priority Date: 08/18/2008
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Kuo, De-Shan, Ko, Ting-Chia, Tu, Chun-Hsiang, Chiu, Po-Shun
• Primary Examiner(s): HENRY, CALEB E
• Application Number:
  US15/357,334
• Publication Number:
  US 20170069810A1
• Time in Patent Office: 449 Days
• Field of Search: 257 88, 438 29
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A light-emitting device comprises a first semiconductor layer; an active layer on the first semiconductor layer; a second semiconductor layer on the active layer; and an electrode structure on the second semiconductor layer, wherein the electrode structure comprises an adhesion layer on the second semiconductor layer, a conductive layer on the adhesion layer, and a bonding layer on the conductive layer, and wherein the electrode structure comprises a center region and an edge region, a thickness of each layer of the edge region of the electrode structure is smaller than that of the center region.

Claims

1. A light-emitting device, comprising:

a first semiconductor layer;

an active layer on the first semiconductor layer;

a second semiconductor layer on the active layer; and

an electrode structure on the second semiconductor layer,

wherein the electrode structure comprises an adhesion layer on the second semiconductor layer, a conductive layer on the adhesion layer, and a bonding layer on the conductive layer, and a barrier layer between the adhesion layer and the conductive layer, wherein the barrier layer comprises a third metal layer and a fourth metal layer, the third metal layer and the fourth metal layer each comprises a material selected from a group consisting of Cr, Pt, Ti, TiW, W, and Zn,

wherein the bonding layer comprises a first metal, the conductive layer comprises a second metal, the second metal has higher standard oxidation potential than the first metal, and

wherein a thickness of the conductive layer is 0.1˜

10 times a thickness of the bonding layer or a total thickness of the conductive layer and the bonding layer is 0.75˜

0.95 times a thickness of the electrode structure.

2. A light-emitting device according to claim 1, wherein the adhesion layer comprises Cr or Rh.

3. A light-emitting device according to claim 1, wherein the adhesion layer comprises a thickness between 5 Å

and 50 Å

.

4. A light-emitting device according to claim 1, further comprising a mirror layer between the adhesion layer and the conductive layer, wherein the mirror layer comprises Al or Ag.

5. A light-emitting device according to claim 4, wherein the mirror layer comprises a thickness between 500 Å

and 5000 Å

.

6. A light-emitting device according to claim 1, wherein the first metal comprises Au, the second metal comprises Al, Ag, or Cu.

7. A light-emitting device according to claim 1, wherein the third metal layer is one to three times thicker than the fourth metal layer.

8. A light-emitting device according to claim 1, wherein the electrode structure comprises a center region and an edge region, a thickness of each layer of the edge region of the electrode structure is smaller than that in the center region.

9. A light-emitting device, comprising:

a first semiconductor layer;

an active layer on the first semiconductor layer;

a second semiconductor layer on the active layer; and

an electrode structure on the second semiconductor layer,

wherein the electrode structure comprises an adhesion layer on the second semiconductor layer, a conductive layer on the adhesion layer, a bonding layer on the conductive layer, and a barrier layer between the bonding layer and the conductive layer,

wherein the barrier layer comprises a third metal layer and a fourth metal layer, the third metal layer and the fourth metal layer each comprises a material selected from a group consisting of Cr, Pt, Ti, TiW, W, and Zn, and

wherein the electrode structure comprises a center region and an edge region, a thickness of the barrier layer at the edge region of the electrode structure is smaller than that at the center region.

10. A light-emitting device according to claim 9, wherein the bonding layer comprises a first metal, the conductive layer comprises a second metal, and the second metal has higher standard oxidation potential than the first metal.

11. A light-emitting device according to claim 9, wherein the adhesion layer comprises Cr or Rh.

12. A light-emitting device according to claim 9, wherein the adhesion layer comprises a thickness between 5 Å

and 50 Å

.

13. A light-emitting device according to claim 9, further comprising a mirror layer between the adhesion layer and the conductive layer, wherein the mirror layer comprises Al or Ag.

14. A light-emitting device according to claim 13, wherein the mirror layer comprises a thickness between 500 Å

and 5000 Å

.

15. A light-emitting device according to claim 10, wherein the first metal comprises Au, the second metal comprises Al, Ag, or Cu.

16. A light-emitting device, comprising:

a first semiconductor layer;

an active layer on the first semiconductor layer;

a second semiconductor layer on the active layer; and

an electrode structure on the second semiconductor layer,

wherein the electrode structure comprises an adhesion layer on the second semiconductor layer, a conductive layer on the adhesion layer, a bonding layer on the conductive layer, and a barrier layer between the bonding layer and the conductive layer, wherein the barrier comprises a third metal layer and a fourth metal layer,

wherein the third metal layer is one to three times thicker than the fourth metal layer, and

wherein the electrode structure comprises a center region and an edge region, a thickness of the barrier layer at the edge region of the electrode structure is smaller than that at the center region.

17. A light-emitting device according to claim 16, wherein the first metal comprises Au, the second metal comprises Al, Ag, or Cu.

18. A light-emitting device according to claim 16, wherein the adhesion layer comprises Cr or Rh.

19. A light-emitting device according to claim 16, further comprising a mirror layer between the adhesion layer and the conductive layer, wherein the mirror layer comprises Al or Ag.