DIODE HAVING VERTICAL STRUCTURE

• US 20130308671A1
• Filed: 07/25/2013
• Published: 11/21/2013
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yoo, Myung Cheol
• Granted Patent: US 9,000,468 B2
• Time in Patent Office: Days
• US Class Current: 372/46.01
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/325 characterised by the doping materials
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• 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
• CPC Class Codes: H01S 5/3013 AIIIBV compounds

Abstract

A light emitting diode includes a conductive layer, an n-GaN layer on the conductive layer, an active layer on the n-GaN layer, a p-GaN layer on the active layer, and a p-electrode on the p-GaN layer. The conductive layer is an n-electrode.

Claims

1. A light emitting device comprising:

a first metal layer comprising Au;

a second metal layer comprising Al on the first metal layer;

a sapphire substrate having a first surface on the second metal layer;

a GaN-based epitaxial layer on a second surface of the sapphire substrate;

a transparent conductive layer on the GaN-based epitaxial layer;

a first electrode on the transparent conductive layer;

a first pad on the first electrode, the first pad including Au;

a second electrode on an etched surface of the GaN-based epitaxial layer; and

a second pad on the second electrode, the second pad including Au,

wherein the first metal layer covers a bottom surface of the second metal layer, and

wherein the second metal layer covers the first surface of the sapphire substrate.

2. The device according to claim 1 wherein the second metal layer has a multi-layer structure.

3. The device according to claim 1 wherein the second metal layer serves as a reflective layer.

4. The device according to claim 1 wherein the second metal layer comprises at least one of Al, Ti, Cr, and Au.

5. The device according to claim 4, wherein the second metal layer comprises a material having different thicknesses that are contemplated.

6. The device according to claim 1 wherein the second metal layer comprises a polished aluminum layer.

7. The device according to claim 1 wherein the first metal layer is configured to serve as a bonding pad.

8. The device according to claim 1 wherein the sapphire substrate has a thickness of less than 120 μ

m.

9. The device according to claim 1 wherein the first surface of the sapphire substrate has an average surface roughness of less than 15 nm.

10. The device according to claim 1 wherein the first surface of the sapphire substrate has an average surface roughness of less than 1 nm.

11. The device according to claim 1 wherein the first surface of the sapphire substrate is polished by at least one of a mechanical polishing and dry etching.

12. The device according to claim 1 wherein the first pad has a thickness of more than 5000 Å

.

13. The device according to claim 1 wherein the second pad has a thickness of more than 5000 Å

.

14. The device according to claim 1 wherein an area of the transparent conductive layer is smaller than an area of the sapphire substrate.

15. The device according to claim 1 wherein the GaN-based epitaxial layer comprises:

a first GaN-based layer on the sapphire substrate;

an active layer on the first GaN-based layer; and

a second GaN-based layer on the active layer.

16. The device according to claim 15, further comprising a clad layer including AlGaN between the active layer and the second GaN-based layer.

17. The device according to claim 15, wherein the transparent conductive layer substantially entirely covers a surface of the second GaN-based layer.

18. The device according to claim 15, wherein the first surface of the sapphire substrate forms an escaping angle for photons to enhance the reflectivity of light from the GaN-base epitaxial layer back through a surface of the second GaN-based layer.

19. The device according to claim 1 wherein the first electrode is formed on an end portion of the transparent conductive layer. The device according to claim 1 wherein the transparent conductive layer comprises at least one of Ni, Au and ITO.