LIGHT EMITTING DIODE AND METHOD FOR MANUFACTURING THE SAME

• US 20120104407A1
• Filed: 06/29/2011
• Published: 05/03/2012
• Est. Priority Date: 10/29/2010
• Status: Abandoned Application

• Current Assignee: Advanced Optoelectronic Technology, Inc.
• Original Assignee: Advanced Optoelectronic Technology, Inc.
• Inventors: HUNG, TZU-CHIEN, SHEN, CHIA-HUI
• Application Number:
  US13/172,734
• Publication Number:
  US 20120104407A1
• Time in Patent Office: Days
• US Class Current: 257/76
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

An LED includes a substrate, a first n-type GaN layer, a connecting layer, a second n-type GaN layer, a light emitting layer, and a p-type GaN layer. The first n-type GaN layer is formed on the substrate, the first n-type GaN layer has a first surface facing away from the substrate, and the first surface includes a first area and a second area. The connecting layer, the second n-type GaN layer, the light emitting layer, and the p-type GaN layer are formed on the first area in sequence. The connecting layer is etchable by alkaline solution; a bottom surface of the second n-type GaN layer facing towards the connecting layer has a roughened exposed portion; the GaN on the bottom surface of the second n-type GaN layer is N-face GaN.

Claims

1. An LED comprising:

a substrate;

a first n-type GaN layer formed on the substrate, the first n-type GaN layer having a first surface facing away from the substrate, the first surface comprising a first area and a second area; and

a connecting layer, a second n-type GaN layer, a light emitting layer, and a p-type GaN layer formed on the first area of the first surface of the first n-type GaN layer in sequence, the connecting layer being etchable by alkaline solution, a bottom surface of the second n-type GaN layer facing towards the connecting layer having an roughed exposed portion, the GaN on the bottom surface of the second n-type GaN layer being N-face GaN.

2. The LED as claimed in claim 1, wherein a p-type electrode is formed on the p-type GaN layer, and an n-type electrode is formed on the second area of the first n-type GaN layer.

3. The LED as claimed in claim 2, wherein the second area of the first surface surrounds the first area of the first surface.

4. The LED as claimed in claim 3, wherein the n-type electrode is frame-shaped and surrounds the first area of the first surface.

5. The LED as claimed in claim 1, wherein a transparent conductive layer is disposed between the p-type electrode and the p-type GaN layer.

6. The LED as claimed in claim 1, wherein the GaN on the first surface of the first n-type GaN layer is Ga-face GaN.

7. The LED as claimed in claim 1, wherein the connecting layer is made of a material selected from a group consisting of AlN, SiO₂, and silicon nitride.

8. The LED as claimed in claim 1, wherein a thickness of the connecting layer is in a range from 5 nm to 1000 nm.

9. A method for manufacturing an LED comprising:

providing a substrate;

forming a first n-type GaN layer, a connecting layer, a second n-type GaN layer, a light emitting layer, and a p-type GaN layer on the substrate in sequence, the connecting layer being etchable by alkaline solution, the GaN on the bottom surface of the second n-type GaN layer being N-face GaN;

etching the p-type GaN layer, the light emitting layer, the second n-type GaN layer, and the connecting layer to expose a portion of the first n-type GaN layer; and

etching a portion of the connecting layer by using alkaline solution to expose a portion of the bottom surface of the second n-type GaN layer, and etching the exposed portion of the bottom surface of the second n-type GaN layer by using the alkaline solution to roughen the exposed portion of the bottom surface of the second n-type GaN layer.

10. The method as claimed in claim 9, further comprising a step of forming a p-type electrode on the p-type GaN layer, and forming an n-type electrode on the exposed portion of the first n-type GaN layer.

11. The method as claimed in claim 10, wherein the exposed portion of the first n-type GaN layer surrounds the connecting layer.

12. The method as claimed in claim 11, wherein the n-type electrode is frame-shaped and surrounds the connecting layer.

13. The method as claimed in claim 10, further comprising a step of forming a transparent conductive layer on the p-type GaN layer before forming the p-type electrode.

14. The method as claimed in claim 9, wherein the GaN on the first surface of the first n-type GaN layer is Ga-face GaN.

15. The method as claimed in claim 9, wherein the connecting layer is made of a material selected from a group consisting of AlN, SiO₂, and silicon nitride.

16. The method as claimed in claim 9, wherein a thickness of the connecting layer is in a range from 5 nm to 1000 nm.

17. The method as claimed in claim 9, wherein the alkaline solution is strong alkaline solution.

18. The method as claimed in claim 17, wherein the strong alkaline solution is KOH solution or NaOH solution.