Gallium nitride based light emitting diode

• US 8,680,571 B2
• Filed: 07/11/2013
• Issued: 03/25/2014
• Est. Priority Date: 07/18/2003
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: Kim, Seong Jae
• Primary Examiner(s): Soward, Ida M
• Application Number:
  US13/939,845
• Publication Number:
  US 20130292697A1
• Time in Patent Office: 257 Days
• Field of Search: 257/13, 257/79, 257/94, 257/103, 257/E33.013, 257/E33.023, 257/E33.025, 257/E33.026, 257/E33.027, 257/E33.028
• US Class Current: 257/103
• CPC Class Codes: H01L 33/0025 comprising only AIIIBV compounds
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A light emitting diode (LED) capable of improving brightness by forming a InGaN layer having a low concentration of indium, and whose lattice constant is similar to that of an active layer of the LED, is provided. The LED includes: a buffer layer disposed on a sapphire substrate; a GaN layer disposed on the buffer layer; a doped GaN layer disposed on the GaN layer; a GaN layer having indium disposed on the GaN layer; an active layer disposed on the GaN layer having indium; and a P-type GaN disposed on the active layer. Here, an empirical formula of the GaN layer having indium is given by In(x)Ga(1−x)N and a range of x is given by 0<x<2, and a thickness of the GaN layer having indium is 50-200 Å.

Claims

1. A light emitting device comprising:

a first conductive type semiconductor layer;

at least one In_xGa<sub>1−

x</sub>N layer (0<

x<

0.2) on the first conductive type semiconductor layer;

at least one GaN layer directly on the at least one In_xGa<sub>1−

x</sub>N layer (0<

x<

0.2);

an active layer directly on the at least one GaN layer;

a second conductive type semiconductor layer on the active layer; and

a transparent layer on the second conductive type semiconductor layer;

wherein the at least one In_xGa<sub>1−

x</sub>N layer (0<

x<

0.2) has a thickness less than 200 Å

.

2. The light emitting device according to claim 1, wherein the transparent layer comprises an ITO (Indium-Tin-Oxide) layer.

3. The light emitting device according to claim 1, wherein the active layer comprises at least three layers.

4. The light emitting device according to claim 2, wherein the active layer comprises a well layer including an InGaN and a barrier layer including a GaN, and wherein a thickness of the barrier layer is more than a thickness of the well layer.

5. The light emitting device according to claim 1, wherein an Indium composition of the at least one In_xGa₁₋

xN layer (0<

x<

0.2) is lower than an Indium composition of the active layer.

6. The light emitting device according to claim 1, wherein the active layer includes at least one well layer and at least one barrier layer formed in 1 period to 7 periods.

7. The light emitting device according to claim 1, further comprising:

an undoped GaN layer having a thickness of 1 μ

m˜

3 μ

m.

8. The light emitting device according to claim 7, wherein a total thickness of the undoped GaN layer and the first conductive type semiconductor layer is 2 μ

m˜

6 μ

m.

9. The light emitting device according to claim 1, wherein a thickness of the at least one GaN layer is 10 Å

˜

30 Å

.

10. The light emitting device according to claim 1, wherein the second conductive type semiconductor layer has a thickness of 750 Å

˜

1500 Å

.

11. The light emitting device according to claim 1, wherein at least one In_xGa₁₋

xN layer (0<

x<

0.2) is directly on the first conductive type semiconductor layer.

12. A light emitting device comprising:

a first conductive type semiconductor layer;

at least one In_xGa<sub>1−

x</sub>N layer (0<

x<

0.2) on the first conductive type semiconductor layer;

an active layer on the at least one In_xGa<sub>1−

x</sub>N layer (0<

x<

0.2);

a second conductive type semiconductor layer on the active layer; and

a transparent ITO (Indium-Tin-Oxide) layer on the second conductive type semiconductor layer;

wherein a thickness of the at least one In_xGa<sub>1−

x</sub>N layer (0<

x<

0.2) is less than a thickness of the second conductive type semiconductor layer having a thickness of 750 Å

˜

1500 Å

.

13. The light emitting device according to claim 12, wherein light generated at the active layer is emitted via the transparent ITO (Indium-Tin-Oxide) layer to an external.

14. The light emitting device according to claim 12, wherein the active layer comprises at least three layers.

15. The light emitting device according to claim 12, wherein the active layer comprises a well layer including an InGaN and a barrier layer including a GaN, and wherein a thickness of the barrier layer is more than a thickness of the well layer.

16. The light emitting device according to claim 12, wherein the active layer comprises a multi-quantum well structure including at least one dopant in at least one of an at least one well layer or an at least one barrier.

17. The light emitting device according to claim 12, wherein the active layer includes at least one well layer and at least one barrier layer formed in 1 period to 7 periods.

18. The light emitting device according to claim 12, further comprising at least one GaN layer directly on the at least one In_xGa₁₋

xN layer (0<

x<

0.2).

19. The light emitting device according to claim 18, wherein a thickness of the at least one GaN layer is 10 Å

˜

30 Å

.

20. The light emitting device according to claim 12, wherein the second conductive type semiconductor layer includes at least one well layer and at least one barrier layer.

21. The light emitting device according to claim 12, wherein the at least one In_xGa₁₋

xN layer (0<

x<

0.2) has a thickness less than 200 Å

.

22. The light emitting device according to claim 12, wherein at least one In_xGa₁₋

xN layer (0<

x<

0.2) is directly on the first conductive type semiconductor layer.

23. A light emitting device comprising:

a first conductive type semiconductor layer;

at least one In_xGa<sub>1−

x</sub>N layer (0<

x<

0.2) on the first conductive type semiconductor layer;

at least one GaN layer directly on the at least one In_xGa<sub>1−

x</sub>N layer (0<

x<

0.2);

an active layer on the at least one GaN layer;

a second conductive type semiconductor layer on the active layer, and

a transparent layer on the second conductive type semiconductor layer;

wherein a thickness of the at least one GaN layer is 10 Å

˜

30 Å

.

24. The light emitting device according to claim 23, wherein the transparent layer comprises a transparent ITO (Indium-Tin-Oxide) layer.

25. The light emitting device according to claim 23, wherein the active layer comprises at least three layers.

26. The light emitting device according to claim 24, wherein the active layer comprises a well layer including an InGaN and a barrier layer including a GaN, and wherein a thickness of the barrier layer is more than a thickness of the well layer.

27. The light emitting device according to claim 23, wherein the active layer comprises a multi-quantum well structure including at least one dopant in at least one of an at least one well layer or an at least one barrier.

28. The light emitting device according to claim 24, wherein the at least one In_xGa₁₋

xN layer (0<

x<

0.2) is directly on the first conductive type semiconductor layer.

29. The light emitting device according to claim 24, wherein the active layer is directly on the at least one GaN layer.

30. The light emitting device according to claim 23, wherein a thickness of the at least one In_xGa₁₋

xN layer (0<

x<

0.2) is less than a thickness of the second conductive type semiconductor layer having a thickness of 750 Å

˜

500 Å

.