LIGHT EMITTING DEVICE AND METHOD OF MANUFACTURING THE SAME

• US 20100176416A1
• Filed: 03/24/2010
• Published: 07/15/2010
• Est. Priority Date: 03/07/2006
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: Gyu Chul Yi, Hyun Kyong Cho, Jin Kyoung Yoo, Jong Wook Kim, Sung Jin An, Young Joon Hong
• Inventors: An, Sung Jin, Hong, Young Joon, Yi, Gyu Chul, Yoo, Jin Kyoung, KIM, Jong Wook, Cho, Hyun Kyong
• Granted Patent: US 8,598,607 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/36 characterised by the electrodes
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A light emitting device and a method of manufacturing the same are disclosed. The light emitting device includes a buffer layer formed on a substrate, a nitride semiconductor layer including a first semiconductor layer, an active layer, and a second semiconductor layer, which are sequentially stacked on the buffer layer, a portion of the first semiconductor layer being exposed to the outside by performing mesa etching from the second semiconductor layer to the portion of the first semiconductor layer, and at least one nanocone formed on the second semiconductor layer.

Claims

1. A light emitting device comprising:

a substrate;

a semiconductor structure including a first-type semiconductor layer on the substrate, an active layer on the first-type semiconductor layer and a second-type semiconductor layer on the active layer, the second-type semiconductor layer having a surface with a first portion and a second portion;

a light extraction structure on the first portion of the surface, and including a plurality of unit structures;

a first electrode on the first-type semiconductor layer; and

a second electrode on the second portion of the surface.

2. The light emitting device according to claim 1, wherein a size of a corresponding unit structure of the plurality of unit structures is nano-scale.

3. The light emitting device according to claim 1, wherein a corresponding unit structure of the plurality of unit structures includes a nanocone.

4. The light emitting device according to claim 1, wherein the light extraction structure includes substantially a same material as that of the semiconductor structure.

5. The light emitting device according to claim 1, wherein the light extraction structure is a part of the semiconductor structure.

6. The light emitting device according to claim 1, wherein a corresponding unit structure of the plurality of unit structures has a pyramid-shape.

7. The light emitting device according to claim 1, wherein a corresponding unit structure of the plurality of unit structures has a size in a range of 10 nm to 1000 nm.

8. The light emitting device according to claim 1, wherein a size of each unit structure of the plurality of unit structures is substantially the same.

9. The light emitting device according to claim 1, wherein the plurality of unit structures do not overlap with each other

10. The light emitting device according to claim 1, wherein a corresponding unit structure of the plurality of unit structures contacts adjacent unit structures.

11. The light emitting device according to claim 1, wherein the light extraction structure includes a nitride semiconductor material having a formula of Al_xIn_yGa_(1-x-y)N (where, 0≦

x≦

1, 0≦

y≦

1, and 0≦

x+y≦

1).

12. The light emitting device according to claim 11, wherein a corresponding unit structure of the plurality of unit structures is formed by controlling a ratio of a horizontal growth of the nitride semiconductor material to a vertical growth of the nitride semiconductor material.

13. The light emitting device according to claim 1, wherein the second portion is located substantially in a center of the surface.

14. The light emitting device according to claim 1, wherein the first portion and the second portion do not overlap each other.

15. The light emitting device according to claim 1, wherein the second electrode is located on the second portion where the light extraction structure is not formed.

16. The light emitting device according to claim 1, wherein the light extraction structure is arranged on the entire surface where the second electrode is not located.

17. The light emitting device according to claim 1, wherein the light extraction structure contacts the second electrode.

18. The light emitting device according to claim 1, wherein at least a part of the plurality of unit structures surrounds the second electrode.

19. The light emitting device according to claim 1, wherein a part of the plurality of unit structures is arranged along a border of the second electrode.

20. The light emitting device according to claim 1, wherein a part of the plurality of unit structures adjoins the second electrode.

21. The light emitting device according to claim 1, wherein the substrate includes one of a sapphire (Al₂O₃) substrate, a silicon carbide (SiC) substrate, a silicon (Si) substrate, a gallium arsenide (GaAs) substrate, or a quartz substrate.

22. The light emitting device according to claim 1, further comprising a transparent conductive layer on the semiconductor structure.

23. The light emitting device according to claim 1, wherein the first electrode or the second electrode includes chrome (Cr), nickel (Ni), gold (Au), aluminum (Al), titanium (Ti), and platinum (Pt), or an alloy thereof.

24. The light emitting device according to claim 1, wherein the first-type semiconductor layer is an n-type semiconductor layer and the second-type semiconductor layer is a p-type semiconductor layer.

25. The light emitting device according to claim 1, wherein the semiconductor structure includes a buffer layer on the substrate.

26. The light emitting device according to claim 1, wherein the first-type semiconductor layer is thicker than the second-type semiconductor layer.

27. The light emitting device according to claim 1, wherein the light extraction structure is configured to enhance a light emission efficiency of the device.

28. The light emitting device according to claim 1, wherein a corresponding unit structure of the plurality of unit structures is formed by a non-etching method.

29. A light emitting device comprising:

a conductive support layer;

a first electrode on the conductive support layer;

a semiconductor structure including a first-type semiconductor layer on the first electrode, an active layer on the first-type semiconductor layer and a second-type semiconductor layer on the active layer, the second-type semiconductor layer having a surface with a first portion and a second portion;

a light extraction structure on the first portion of the surface, and including a plurality of unit structures; and

a second electrode on the second portion of the surface.

30. The light emitting device according to claim 29, wherein a size of a corresponding unit structure of the plurality of unit structures is nano-scale.

31. The light emitting device according to claim 29, wherein a corresponding unit structure of the plurality of unit structures includes a nanocone.

32. The light emitting device according to claim 29, wherein the light extraction structure includes substantially a same material as that of the semiconductor structure.

33. The light emitting device according to claim 29, wherein the light extraction structure is a part of the semiconductor structure.

34. The light emitting device according to claim 29, wherein a corresponding unit structure of the plurality of unit structures has a pyramid-shape.

35. The light emitting device according to claim 29, wherein a corresponding unit structure of the plurality of unit structures has a size in a range of 10 nm to 1000 nm.

36. The light emitting device according to claim 29, wherein a size of each unit structure of the plurality of unit structures is substantially the same.

37. The light emitting device according to claim 29, wherein the plurality of unit structures do not overlap each other.

38. The light emitting device according to claim 29, wherein a corresponding unit structure of the plurality of unit structures contacts adjacent unit structures.

39. The light emitting device according to claim 29, wherein the light extraction structure includes a nitride semiconductor material having a formula of Al_xIn_yGa_(1-x-y)N (where, 0≦

x≦

1, 0≦

y≦

1, and 0≦

x+y≦

1).

40. The light emitting device according to claim 39, wherein a corresponding unit structure of the plurality of unit structures is formed by controlling a ratio of a horizontal growth of the nitride semiconductor material to a vertical growth of the nitride semiconductor material.

41. The light emitting device according to claim 29, wherein the first portion and the second portion do not overlap each other.

42. The light emitting device according to claim 29, wherein the second electrode is located on the second portion where the light extraction structure is not formed.

43. The light emitting device according to claim 29, wherein the light extraction structure is arranged on the entire surface where the second electrode is not located.

44. The light emitting device according to claim 29, wherein the light extraction structure contacts the second electrode.

45. The light emitting device according to claim 29, wherein at least a part of the plurality of unit structures surrounds the second electrode.

46. The light emitting device according to claim 29, wherein a part of the plurality of unit structures is arranged along a border of the second electrode.

47. The light emitting device according to claim 29, wherein a part of the plurality of unit structures adjoins the second electrode.

48. The light emitting device according to claim 29, wherein the second portion is located substantially in a center of the surface.

49. The light emitting device according to claim 29, wherein the substrate includes one of a sapphire (Al₂O₃) substrate, a silicon carbide (SiC) substrate, a silicon (Si) substrate, a gallium arsenide (GaAs) substrate, or a quartz substrate.

50. The light emitting device according to claim 29, wherein the first electrode or the second electrode includes chrome (Cr), nickel (Ni), gold (Au), aluminum (Al), titanium (Ti), and platinum (Pt), or an alloy thereof.

51. The light emitting device according to claim 29, wherein the first-type semiconductor layer is a p-type semiconductor layer and the second-type semiconductor layer is an n-type semiconductor layer.

52. The light emitting device according to claim 29, wherein the conductive support layer includes soft metal and/or hard metal.

53. The light emitting device according to claim 52, wherein the soft metal includes a material selected from the group consisting of gold (Au), copper (Cu), silver (Ag), and aluminum (Al), and the hard metal includes a material selected from the group consisting of nickel (Ni), cobalt (Co), and palladium (Pd).

54. The light emitting device according to claim 29, wherein the first electrode contacts the semiconductor structure.

55. The light emitting device according to claim 29, wherein the conductive support structure contacts the first electrode.

56. The light emitting device according to claim 29, wherein the first electrode and the second electrode are located on opposite surfaces of the semiconductor structure.

57. The light emitting device according to claim 29, wherein the first-type semiconductor layer has a surface facing the first electrode, and

wherein the first electrode covers substantially the entire surface of the first-type semiconductor layer.

58. The light emitting device according to claim 29, wherein the conductive support layer and the first electrode have surfaces that face each other, and

wherein areas of the surfaces are substantially the same.

59. The light emitting device according to claim 29, wherein the light extraction structure is configured to enhance the light emission efficiency of the device.

60. The light emitting device according to claim 29, wherein a corresponding unit structure of the plurality of unit structures is formed by a non-etching method.

61. The light emitting device according to claim 29, wherein the first electrode is configured to enhance a reflectivity of light emitted from the active layer.