Vertical GaN-based LED and method of manfacturing the same

• US 20070018187A1
• Filed: 07/21/2006
• Published: 01/25/2007
• Est. Priority Date: 07/22/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Lee, Jae, Choi, Hee, Oh, Jeong, Lee, Su, Choi, Seok, Oh, Bang
• Granted Patent: US 7,436,001 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers

Abstract

A vertical GaN-based LED and a method of manufacturing the same are provided. The vertical GaN-based LED includes an n-electrode, a first n-type GaN layer, a first AlGaN layer, a GaN layer, a second AlGaN layer, a second n-type GaN layer, an active layer, a p-type GaN layer, and a structure support layer. The first n-type GaN layer has uneven patterns having a plurality of protuberances. The first AlGaN layer is formed under the first n-type GaN layer, and the GaN layer is formed under the first AlGaN layer. The active layer is formed under the second n-type GaN layer, and the p-type GaN layer is formed under the active layer. A p-electrode is formed under the p-type GaN layer, and the structure support layer is formed under the p-electrode.

Claims

1. A vertical GaN-based LED (light emitting diode) comprising:

an n-electrode;

a first n-type GaN layer having uneven patterns including a plurality of protuberances for increasing a surface area and formed under the n-electrode;

a first AlGaN layer formed under the first n-type GaN layer;

a GaN layer formed under the first AlGaN layer;

a second AlGaN layer formed under the GaN layer;

a second n-type GaN layer formed under the second AlGaN layer;

an active layer formed under the second n-type GaN layer;

a p-type GaN layer formed under the active layer;

a p-electrode formed under the p-type GaN layer; and

a structure support layer formed under the p-electrode.

2. The vertical GaN-based LED according to claim 1,

wherein each of the uneven patterns has a lower width of 0.5 μ

m to 5 μ

m.

3. The vertical GaN-based LED according to claim 1,

wherein each of the uneven patterns has a height of 0.1 μ

m to 5 μ

m.

4. The vertical GaN-based LED according to claim 1,

wherein each of the uneven patterns has a lateral side tapered upwardly.

5. The vertical GaN-based LED according to claim 4,

wherein the uneven patterns are hemispherical patterns arranged vertically and horizontally.

6. The vertical GaN-based LED according to claim 1,

wherein the uneven patterns are arranged at an interval of 0.1 μ

m to 5 μ

m.

7. The vertical GaN-based LED according to claim 1 further comprising

a plurality of protuberances additionally formed in regions between the uneven patterns.

8. The vertical GaN-based LED according to claim 7,

wherein the plurality of protuberances are formed at a period of 0.001 μ

m to 5 μ

m.

9. The vertical GaN-based LED according to claim 7,

wherein the plurality of protuberances are formed to have a height of 0.001 μ

m to 2 μ

m.

10. The vertical GaN-based LED according to claim 1,

wherein each of the first AlGaN layer and the second AlGaN layer has a thickness of 100 Å

to 500 Å

.

11. The vertical GaN-based LED according to claim 1,

wherein Al content of the first AlGaN layer and the second AlGaN layer is in the range of 10% to 50%.

12. The vertical GaN-based LED according to claim 1,

wherein each of the first AlGaN layer and the second AlGaN layer is an undoped AlGaN layer.

13. The vertical GaN-based LED according to claim 1,

wherein each of the first AlGaN layer and the second AlGaN layer is an AlGaN layer doped with n-type impurities.

14. The vertical GaN-based LED according to claim 1,

wherein each of the first AlGaN layer and the second AlGaN layer includes silicon or oxygen as impurities.

15. The vertical GaN-based LED according to claim 1,

wherein the GaN layer has a thickness of 50 Å

to 500 Å

.

16. The vertical GaN-based LED according to claim 1,

wherein the GaN layer is an undoped GaN layer.

17. The vertical GaN-based LED according to claim 1,

wherein the GaN layer is an AlGaN layer doped with n-type impurities.

18. The vertical GaN-based LED according to claim 1 further comprising

a transparent conductor layer located between the n-electrode and the first n-type GaN layer and formed on the entire surface of the first n-type GaN layer.

19. The vertical GaN-based LED according to claim 1 further comprising

a 2D (two-dimensional) electron-gas layer located at the interface between the first AlGaN layer and the GaN layer and an interface between the GaN layer and the second AlGaN layer.

20. A method for manufacturing a vertical GaN-based LED, comprising:

patterning the surface of a sapphire substrate into uneven patterns;

forming a buffer layer on the sapphire substrate patterned into the uneven patterns;

forming a first n-type GaN layer on the buffer layer;

forming a first AlGaN layer on the first n-type GaN layer;

forming a GaN layer on the first AlGaN layer such that a 2D-electron gas layer is formed on a junction interface of the first AlGaN layer;

forming a second AlGaN layer on the GaN layer such that a 2D-electron gas layer is formed on a junction interface of the GaN layer;

forming a second n-type GaN layer on the second AlGaN layer;

forming an active layer on the second n-type GaN layer;

forming a p-type GaN layer on the active layer;

forming a p-electrode on the p-type GaN layer;

forming a structure support layer on the p-electrode;

removing the sapphire substrate to expose the buffer layer having a surface of the uneven patterns;

etching the exposed buffer layer and the surface of the first n-type GaN layer such that the surface of the first n-type GaN layer has uneven patterns;

forming a plurality of protuberances on the surface of the first n-type GaN layer that has the uneven patterns; and

forming an n-electrode on the first n-type GaN layer where the plurality of protuberances are formed.

21. The method according to claim 20,

wherein the patterning of the surface of the sapphire substrate includes:

forming a photoresist pattern having a predetermined shape on the sapphire substrate;

processing the photoresist pattern such that the photoresist pattern has a desired cross-sectional shape; and

etching the processed photoresist pattern and the sapphire substrate, simultaneously, to pattern a surface of the sapphire substrate into uneven patterns.

22. The method according to claim 21,

wherein, in the processing of the photoresist pattern, the photoresist pattern is re-flowed so that the photoresist pattern patterns have a lateral side tapered upwardly.

23. The method according to claim 22,

wherein the processed photoresist patterns are hemispherical patterns arranged vertically and horizontally.

24. The method according to claim 20,

wherein, in the forming of the plurality of protuberances, wet etching is performed on the surface of the first n-type GaN layer where the uneven patterns are formed.

25. The method according to claim 20 further comprising

annealing the AlGaN layer under oxygen atmosphere, after the forming of the first AlGaN layer and the second AlGaN layer.

26. The method according to claim 20 further comprising

forming a transparent conductor layer on the first n-type GaN layer, before the forming of the n-electrode.