Diode having vertical structure and method of manufacturing the same

• US 20030080344A1
• Filed: 10/26/2001
• Published: 05/01/2003
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yoo, Myung Cheol
• Granted Patent: US 7,148,520 B2
• Time in Patent Office: Days
• US Class Current: 257/103
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/325 characterised by the doping materials
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01S 5/3013 AIIIBV compounds

Abstract

A light emitting diode includes a conductive layer, an n-GaN layer on the conductive layer, an active layer on the n-GaN layer, a p-GaN layer on the active layer, and a p-electrode on the p-GaN layer. The conductive layer is an n-electrode.

Claims

1. A light emitting diode comprising:

a conductive layer;

an n-GaN layer on the conductive layer;

an active layer on the n-GaN layer;

a p-GaN layer on the active layer; and

a p-electrode on the p-GaN layer;

wherein the conductive layer is an n-electrode.

2. The light emitting diode according to claim 1, wherein the conductive layer also acts as a reflective layer to reflect light from the active layer.

3. The light emitting diode according to claim 1, wherein the conductive layer is made of aluminum.

4. The light emitting diode according to claim 1, wherein the conductive layer includes a metal selected from the group consisting of aluminum, gold, palladium, titanium, indium, nickel and platinum.

5. The light emitting diode according to claim 4, wherein the conductive layer includes aluminum having a concentration of about 99.999% or higher.

6. The light emitting diode according to claim 1, wherein the conductive layer includes aluminum of about 3000 Å

.

7. The light emitting diode according to claim 1, wherein the conductive layer entirely covers one side of the n-GaN layer.

8. The light emitting diode according to claim 1, further comprising a buffer layer between the conductive layer and the n-GaN layer.

9. The light emitting diode according to claim 1, wherein the buffer layer includes n-GaN.

10. The light emitting diode according to claim 1, further comprising a p-transparent contact between the p-electrode and the p-GaN layer.

11. The light emitting diode according to claim 10, wherein the p-transparent contact includes indium-tin-oxide.

12. The light emitting diode according to claim 1, further comprising a metal pad on the p-electrode.

13. The light emitting diode according to claim 12, wherein the metal pad is about 5000 Å

or higher.

14. The light emitting diode according to claim 12, wherein the metal pad includes Au.

15. The light emitting diode according to claim 1, wherein the conductive layer includes Ti and Al (Ti/Al)

16. The light emitting diode according to claim 1, wherein the conductive layer includes a material selected from the group consisting of Ti/Al, Cr/Au and Ti/Au.

17. The light emitting diode according to claim 1, wherein the p-electrode includes Ni and Au (Ni/Au).

18. The light emitting diode according to claim 1, wherein the p-electrode includes a material selected from the group consisting of Ni/Au, Pd/Au, Pd/Ni and Pt.

19. The light emitting diode according to claim 1, wherein the active layer includes AlInGaN.

20. The light emitting diode according to claim 1, wherein the active layer includes at least one of a quantum well layer and a double hetero structure

21. The light emitting diode according to claim 1, wherein the quantum layer includes a multiple quantum layer.

22. The light emitting diode according to claim 1, further comprising a cladding layer between the p-GaN layer and the active layer.

23. A light emitting diode comprising:

a first electrode;

an n-type layer and a p-type layer on the first electrode;

an active layer between the n-type layer and the p-type layer; and

a second electrode contacting the p-type layer;

wherein the first electrode contacts the n-type layer and acts as a reflective layer to reflect light from the active layer.

24. The light emitting diode according to claim 23, wherein the reflective layer entirely covers the n-type layer.

25. The light emitting diode according to claim 23, wherein the reflective layer includes aluminum.

26. The light emitting diode according to claim 25, wherein the aluminum has a concentration of about 99.999% or higher

27. The light emitting diode according to claim 23, further comprising a buffer layer between the first electrode and the n-type layer.

28. The light emitting diode according to claim 27, wherein the buffer layer includes n-GaN.

29. The light emitting diode according to claim 23, wherein the active layer includes at least one of a quantum well layer and a double hetero structure

30. The light emitting diode according to claim 23, wherein the quantum layer includes a multiple quantum layer.

31. A method of making a diode comprising:

forming a first n-GaN layer on a substrate;

forming an active layer on the first n-GaN layer;

forming a p-GaN layer on the active layer;

separating the substrate from the first n-GaN layer;

forming an n-type contact layer on the n-GaN layer;

forming a p-electrode on the p-GaN layer.

wherein the n-type contact layer acts as a reflective layer to reflect light from the active layer.

32. The method according to claim 31, wherein the p-electrode is formed prior to separating the substrate.

33. The method according to claim 31, further comprising forming a second n-GaN layer between the substrate and the first n-GaN layer.

34. The method according to claim 33, wherein the second n-GaN is formed using metal organic chemical vapor deposition (MOCVD).

35. The method according to claim 31, wherein the substrate includes sapphire.

36. The method according to claim 31, wherein the substrate is separated from the first n-GaN using a laser.

37. The method according to claim 31, further comprising forming a transparent conductive layer between the p-electrode and the p-GaN layer.

38. A diode comprising:

a first electrode having an epitaxially grown GaN layer on one side of the first electrode;

a second electrode;

an active layer between the first and second electrodes;

wherein the first electrode is a reflective layer to reflect light from the active layer.

39. The lighting device according to claim 38, wherein the reflective layer maximizes light extracted from the diode.

40. A method of forming a diode comprising:

forming an second GaN layer on a substrate having a first GaN layer;

forming an active layer on the second GaN layer;

forming a third GaN layer on the active layer;

separating the substrate from the first GaN layer; and

forming a first electrode on the first GaN layer where the substrate was separated;

wherein the first electrode is a reflective layer to reflect light from the active layer.

41. The method according to claim 40, wherein the second GaN layer is formed on the first GaN layer using metal organic chemical vapor deposition (MOCVD).

42. The method according to claim 40, wherein the first GaN layer is epitaxially grown on the substrate.

43. The method according to claim 40, wherein the substrate is separated using laser.

44. The method according to claim 40, wherein the active layer includes a multiple quantum well.

45. The method according to claim 40, wherein the substrate includes sapphire.

46. The method according to claim 40, wherein the first electrode includes aluminum.

47. A light emitting diode comprising:

a reflective conductive layer of a first polarity;

a first GaN layer of the first polarity on the reflective conductive layer;

an active layer on the first GaN layer;

a second GaN layer of a second polarity on the active layer; and

an electrode of the second polarity on the second GaN layer.

48. The light emitting diode according to claim 47, further comprising a transparent conductive layer between the second GaN layer and the electrode.

49. The light emitting diode according to claim 47, wherein the reflective layer includes a conductive material and acts as an electrode of the first polarity.

50. The light emitting diode according to claim 47, wherein the reflective layer has substantially a same surface area as the first GaN layer.

51. The light emitting diode according to claim 47, wherein the first polarity is n-type and the second polarity is p-type.

52. The light emitting diode according to claim 47, further comprising a cladding layer between the active layer and the second GaN layer.

53. The light emitting diode according to claim 52, wherein the cladding layer including AlGaN.

54. The light emitting diode according to claim 47, wherein the active layer includes at least one of a quantum well layer and a double hetero structure

55. The light emitting diode according to claim 47, wherein the quantum layer includes a multiple quantum well layer.

56. A method of making a light emitting diode having an n-contact comprising:

forming an n-GaN on a first side of a n-GaN buffer layer;

forming an AlInGaN active layer on the n-GaN layer;

forming a cladding layer on the AlInGaN active layer;

forming a p-GaN layer on the p-AlGaN cladding layer;

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

forming a transparent conductive layer on the p-GaN layer; and

forming an n-type electrode on a second side of the n-GaN buffer layer.

57. The light emitting diode according to claim 56, wherein the cladding layer includes p-AlGaN.

58. The light emitting diode according to claim 56, wherein the cladding layer is formed by metal organic chemical vapor deposition (MOCVD).

59. A diode comprising:

a buffer layer having first and second surfaces;

an n-GaN layer on the first surface of the buffer layer;

an active layer on the n-GaN layer;

a p-GaN layer on the active layer;

a p-electrode on the p-GaN layer; and

an n-electrode on the second surface of the buffer layer.

60. The diode according to claim 59, further comprising a cladding layer formed between the active layer and the p-GaN layer.

61. The diode according to claim 60, wherein the cladding layer includes p-AlGaN.

62. The diode according to claim 59, wherein a metal transparent contact is formed on the p-GaN layer.

63. The diode according to claim 62, wherein a metal pad is formed on a side of the metal transparent contact.