Thin film light emitting diode

• US 7,956,364 B2
• Filed: 01/12/2010
• Issued: 06/07/2011
• Est. Priority Date: 06/26/2002
• Status: Expired due to Fees

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yoo, Myung Cheol
• Primary Examiner(s): Ha; Nathan W
• Application Number:
  US12/654,992
• Publication Number:
  US 20100171125A1
• Time in Patent Office: 511 Days
• Field of Search: 257 98-100, 257/143, 257 79- 81, 257/E33.062, 257/76
• US Class Current: 257/76
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/4918 being disposed on at least two different sides of the body, e.g. dual array
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials
• CPC Class Codes: H01L 33/504 : Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/507 : the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• 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

Abstract

Light emitting LEDs devices comprised of LED chips that emit light at a first wavelength, and a thin film layer over the LED chip that changes the color of the emitted light. For example, a blue LED chip can be used to produce white light. The thin film layer beneficially consists of a florescent material, such as a phosphor, and/or includes tin. The thin film layer is beneficially deposited using chemical vapor deposition.

Claims

1. A vertical topology light emitting device, comprising:

a conductive support structure;

an adhesion structure over the conductive support structure;

a semiconductor structure over the adhesion structure, wherein the semiconductor structure has a first surface, a second surface and a side surface;

a reflective structure between the adhesion structure and the first surface of the semiconductor structure, the reflective structure also serving as a first electrode, wherein the reflective structure is configured to reflect the light from the semiconductor structure;

a second electrode over the second surface of the semiconductor structure, wherein the second surface is opposite the first surface;

a passivation layer over the semiconductor structure; and

a wavelength converting layer over the second surface of the semiconductor structure.

2. The device according to claim 1, wherein the passivation layer comprises an insulative material.

3. The device according to claim 2, wherein the insulative material comprises at least one of Si, epoxy, oxides, and nitrides.

4. The device according to claim 1, wherein the passivation layer is an electrically insulative layer.

5. The device according to claim 1, wherein the passivation layer contacts the wavelength converting layer.

6. The device according to claim 1, wherein the passivation layer is at least partially disposed between the semiconductor structure and the wavelength converting layer.

7. The device according to claim 1, wherein the passivation layer is disposed over the first surface of the semiconductor structure.

8. The device according to claim 1, wherein the passivation layer is disposed over the side surface of the semiconductor structure.

9. The device according to claim 1, wherein the passivation layer is disposed over the second surface of the semiconductor structure.

10. The device according to claim 1, wherein the passivation layer is disposed over the first surface and the side surface of the semiconductor structure.

11. The device according to claim 1, wherein the reflective structure covers substantially the entire area of the first surface of the semiconductor structure.

12. The device according to claim 1, wherein the wavelength converting layer comprises at least one of a fluorescent material, a tin-containing material, and a phosphor.

13. The device according to claim 1, wherein the reflective structure comprises:

a reflective layer; and

a metal contact over the reflective layer.

14. The device according to claim 1, wherein the passivation layer has a portion for an external electrical connection.

15. The device according to claim 14, wherein the portion is an open space corresponding to the second electrode.

16. The device according to claim 1, wherein the wavelength converting layer has an open space corresponding to the second electrode.

17. The device according to claim 16, wherein the passivation layer has an open space corresponding to the open space of the wavelength converting layer.

18. The device according to claim 17, wherein the open space of the passivation layer is aligned with the open space of the wavelength converting layer.

19. The device according to claim 1, wherein the wavelength converting layer has a substantially uniform thickness.

20. The device according to claim 1, wherein the passivation layer is disposed between the wavelength converting layer and the semiconductor structure.

21. The device according to claim 20, wherein the passivation layer electrically insulates the wavelength converting layer from the semiconductor structure.

22. The device according to claim 1, wherein the wavelength converting layer has a substantially uniform thickness over at least one of the second surface and the side surface of the semiconductor structure, or portions thereof.

23. The device according to claim 1, wherein the wavelength converting layer has a substantially uniform thickness over at least one of a side surface of the reflective structure, and a side surface of the second electrode, or portions thereof.

24. The device according to claim 1, wherein the wavelength converting layer is disposed over substantially the entire surface of the passivation layer.

25. The device according to claim 1, wherein the passivation layer is disposed over the second surface and the side surface of the semiconductor structure, or portions thereof.

26. The device according to claim 1, wherein the passivation layer is disposed over the side surface of the semiconductor structure and extends to at least a portion of the second surface of the semiconductor structure.

27. The device according to claim 1, wherein the passivation layer is disposed over substantially the entire second surface of the semiconductor structure not covered by the second electrode.

28. The device according to claim 1, wherein the passivation layer is disposed over substantially the entire side surface of the semiconductor structure.

29. The device according to claim 1, wherein the passivation layer has a substantially uniform thickness.

30. The device according to claim 29, wherein the substantially uniform thickness of the passivation layer is configured to enhance the uniformity of light emitted from the device.

31. The device according to claim 1, wherein the thickness of the wavelength converting layer is about 10 microns or so thick.

32. The device according to claim 1, wherein the thickness of the passivation layer is about 1000 Å

.

33. The device according to claim 1, wherein at least a portion of the passivation layer prevents the wavelength converting layer from contacting with the semiconductor structure.

34. The device according to claim 1, wherein the second electrode comprises nickel.

35. The device according to claim 1, wherein the conductive support structure comprises a thermally conductive material.

36. The device according to claim 1, wherein the conductive support structure comprises an electrically conductive material.

37. The device according to claim 1, wherein the conductive support structure is less than about 100 microns thick.

38. The device according to claim 1, wherein the conductive support structure comprises at least one of Cu, Al, or Au.

39. The device according to claim 1, wherein the adhesion structure comprises at least one of Au or Cr.

40. The device according to claim 1, wherein the adhesion structure comprises a first metallic layer and a second metallic layer.

41. The device according to claim 40, wherein the first metallic layer contacts the conductive support structure.

42. The device according to claim 40, wherein the second metallic layer contacts the reflective structure.

43. The device according to claim 1, wherein the adhesion structure contacts the reflective structure.

44. The device according to claim 1, wherein the adhesion structure and the conductive support structure have surfaces that face each other, and wherein the areas of the surfaces are substantially the same.

45. The device according to claim 44, wherein the adhesion structure surface and the conductive support structure surface contact each other.

46. The device according to claim 1, wherein the reflective structure is configured to reflect the light from the semiconductor structure back through the second surface of the semiconductor structure.

47. The device according to claim 1, wherein the reflective structure is multilayer.

48. The device according to claim 47, wherein at least one layer of the reflective structure comprises aluminum or titanium.

49. The device according to claim 1, further comprising a metal contact pad over the second electrode.

50. The device according to claim 49, wherein the metal contact pad comprises at least one of Pd, Pt, Au, or Al.

51. The device according to claim 49, wherein the metal contact pad has a diameter of about 100 microns.

52. The device according to claim 49, further comprising a bonding wire electrically connected to the metal contact pad.

53. The device according to claim 1, wherein the second electrode comprises a transparent contact.

54. The device according to claim 1, wherein the conductive support structure comprises a metal support layer.

55. The device according to claim 1, wherein the passivation layer is disposed higher than the second electrode.

56. The device according to claim 1, wherein the passivation layer is disposed over at least a portion of the second electrode.

57. The device according to claim 1, wherein the passivation layer is disposed over at least a portion of the reflective structure.

58. The device according to claim 1, wherein the passivation layer contacts the reflective structure.

59. The device according to claim 1, wherein the passivation layer contacts the second electrode.

60. The device according to claim 1, wherein the second electrode contacts the second surface of the semiconductor structure.

61. The device according to claim 1, wherein the passivation layer contacts at least a part of the second surface of the semiconductor structure.

62. The device according to claim 61, wherein the reflective structure contacts the first surface of the semiconductor structure, and wherein the contact area between the reflective structure and the first surface of the semiconductor structure is larger than the contact area between the passivation layer and the second surface of the semiconductor structure.

63. The device according to claim 61, wherein the passivation layer extends along the second surface of the semiconductor structure in the direction of the second electrode.

64. The device according to claim 63, wherein the passivation layer extends along the second surface of the semiconductor structure and contacts the second electrode.

65. The device according to claim 1, wherein the semiconductor structure comprises:

a first-type semiconductor layer over the reflective structure;

a second-type semiconductor layer over the first-type semiconductor layer; and

a light emitting layer disposed between the first-type semiconductor layer and the second- type semiconductor layer.

66. The device according to claim 65, wherein the first-type semiconductor layer is an n-type GaN-based layer and the second-type semiconductor layer is a p-type GaN-based layer.

67. The device according to claim 1, wherein the reflective structure comprises a first layer and a second layer, wherein the first layer and the second layer comprise different materials.

68. The device according to claim 1, wherein the device is a part of an LED package.

69. The device according to claim 1, wherein the LED package comprises a heat sink.