Gallium nitride based light emitting diode and fabrication method thereof

• US 8,674,337 B2
• Filed: 06/27/2011
• Issued: 03/18/2014
• 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:
  US13/169,887
• Publication Number:
  US 20110253978A1
• Time in Patent Office: 995 Days
• Field of Search: 257/12.15, 257/22, 257/183, 257/189, 257/190, 257/200, 257/E25.028, 257/E25.032, 257/E33.025, 257/E33.028, 257/E33.031, 257/E33.033, 257/E33.034, 257/E33.049
• US Class Current: 257/12
• 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) and a method for fabricating the same, 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. An LED comprising:

a first conductive type semiconductor layer;

at least one In_xGa<sub>1−

x</sub>N layer (0<

×

<

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<

×

<

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 around the second conductive type semiconductor layer.

2. The LED according to claim 1, wherein the active layer comprises a multi-quantum well structure including InGaN.

3. The LED according to claim 2, wherein the multi-quantum well structure includes an InGaN/GaN structure.

4. The LED according to claim 1, wherein the at least one In_xGa₁₋

xN layer (0<

×

<

0.2) has a thickness less than 200 Å

.

5. The LED according to claim 1, wherein the second conductive type semiconductor layer includes at least one well layer and at least one barrier layer.

6. The LED according to claim 1, wherein the transparent layer includes ITO (Indium-Tin-Oxide).

7. The LED according to claim 6, wherein light generated at the active layer is emitted via the transparent layer including ITO (Indium-Tin-Oxide) to an external.

8. The LED according to claim 1, wherein the second conductive type semiconductor layer has a thickness of 750 Å

˜

1500 Å

.

9. The LED according to claim 1, wherein a thickness of the first conductive type semiconductor layer is 1 μ

m˜

3 μ

m.

10. The LED according to claim 1, further comprising:

an undoped GaN layer under the first conductive type semiconductor layer.

11. The LED according to claim 10, wherein a thickness of the undoped GaN layer is 1 μ

m˜

3 μ

m.

12. The LED according to claim 10, wherein a total thickness of the undoped GaN layer and the first conductive type semiconductor layer is 2 μ

m˜

6 μ

m.

13. The LED according to claim 1, wherein an Indium composition of the at least one In_xGa₁₋

xN layer (0<

×

<

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

14. The LED according to claim 1, wherein a thickness of the at least one GaN layer is 10 Å

˜

30 Å

.

15. The LED according to claim 1, 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.

16. The LED according to claim 1, wherein the active layer comprises at least three layers.

17. The LED according to claim 1, wherein the active layer comprises a well layer and a barrier layer, and wherein a thickness of the barrier layer is more than a thickness of the well layer.

18. The LED 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.

19. A light emitting device, comprising:

a substrate;

a first conductive type semiconductor layer on the substrate;

at least one In_xGa<sub>1−

x</sub>N layer (0<

×

<

0.2) on the first conductive type semiconductor layer;

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

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.

20. The light emitting device according to claim 19, wherein the active layer comprises a multi-quantum well structure including InGaN.

21. The light emitting device according to claim 20, wherein the multi-quantum well structure includes an InGaN/GaN structure.

22. The light emitting device according to claim 19, wherein the at least one In_xGa₁₋

xN layer (0<

×

<

0.2) has a thickness less than 200Å

.

23. The light emitting device according to claim 19, wherein the second conductive type semiconductor layer includes at least one well layer and at least one barrier layer.

24. The light emitting device according to claim 19, wherein the second conductive type semiconductor layer has a thickness of 750 Å

˜

1500 Å

.

25. The light emitting device according to claim 19, wherein a thickness of the first conductive type semiconductor layer is 1 μ

m˜

3 μ

m.

26. The light emitting device according to claim 19, further comprising:

an undoped GaN layer under the first conductive type semiconductor layer.

27. The light emitting device according to claim 26, wherein a thickness of the undoped GaN layer is 1 μ

m˜

3 μ

m.

28. The light emitting device according to claim 27, wherein a total thickness of the undoped GaN layer and the first conductive type semiconductor layer is 2 μ

m˜

6 μ

m.

29. The light emitting device according to claim 19, wherein an Indium composition of the at least one In_xGa₁₋

N layer (0<

×

<

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

30. The light emitting device according to claim 19, wherein light generated at the active layer is emitted via the transparent ITO (Indium-Tin-Oxide) layer to an external.

31. The light emitting device according to claim 19, 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.

32. The light emitting device according to claim 19, wherein the active layer comprises at least three layers.

33. The light emitting device according to claim 19, wherein the active layer comprises a well layer and a barrier layer, and wherein a thickness of the barrier layer is more than a thickness of the well layer.

34. The light emitting device according to claim 19, wherein the active layer includes at least one well layer and at least one barrier layer formed in 1 period to 7 periods.

35. The light emitting device according to claim 19, further comprising:

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

x</sub>N layer (0<

×

<

0.2).

36. The light emitting device according to claim 35, wherein a thickness of the at least one GaN layer is 10 Å

˜

30 Å

.

37. A light emitting device comprising:

a first conductive type semiconductor layer;

at least one In_xGa<sub>1−

x</sub>N layer (0<

×

<

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<

×

<

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 around the second conductive type semiconductor layer, wherein the active layer comprises a multi-quantum well structure including Indium, and wherein the second conductive type semiconductor layer has a thickness of 750 Å

˜

1500 Å

.

38. The light emitting device according to claim 37, wherein the active layer includes at least one well layer and at least one barrier layer formed in 1 period to 7 periods.

39. The light emitting device according to claim 37, wherein the transparent layer includes ITO (Indium-Tin-Oxide).

40. The light emitting device according to claim 37, wherein a thickness of the at least one GaN layer is 10 Å

˜

30 Å

.

41. The light emitting device according to claim 37, wherein the at least one In_xGa₁₋

xN layer (0<

×

<

0.2) has a thickness less than 200 Å

.

42. The light emitting device according to claim 37, wherein at least one In_xGa₁₋

xN layer (0<

×

<

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