High output group III nitride light emitting diodes

• US 20060060872A1
• Filed: 04/22/2005
• Published: 03/23/2006
• Est. Priority Date: 09/22/2004
• Status: Active Grant

• Current Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Edmond, John Adam, Bergmann, Michael J., Haberern, Kevin Ward, Emerson, David T.
• Granted Patent: US 7,737,459 B2
• Time in Patent Office: Days
• US Class Current: 257/94
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/325 characterised by the doping materials

Abstract

A light emitting diode is disclosed that includes a silicon carbide substrate and a light emitting structure formed from the Group III nitride material system on the substrate. The diode has an area greater than 100,000 square microns and has a radiant flux at 20 milliamps current of at least 29 milliwatts at its dominant wavelength between 390 and 540 nanometers.

Claims

1. A light emitting diode having an area greater than 100,000 square microns and a radiant flux at 20 milliamps current of at least 29 milliwatts at its dominant wavelength between 390 and 540 nanometers.

2. A light emitting diode according to claim 1 comprising a light emitting structure formed from the Group III nitride material system.

3. A light emitting diode according to claim 2 comprising a silicon carbide single crystal substrate.

4. A light emitting diode according to claim 1 having at least one side that is at least 400 microns in length.

5. A light emitting diode according to claim 1 having a radiant flux at 20 milliamps current of at least 29 milliwatts at its dominant wavelength between 450 and 460 nanometers.

6. A light emitting diode according to claim 1 having a radiant flux at 20 milliamps current of at least 30 milliwatts at its dominant wavelength of about 453 nanometers.

7. A light emitting diode according to claim 5 having an area of about 200,000 square microns.

8. A light emitting diode according to claim 1 having a radiant flux of at least 12 milliwatts at its dominant wavelength between 520 and 540 nanometers.

9. A light emitting diode according to claim 1 having a radiant flux of at least 13 milliwatts at its dominant wavelength between 524 and 535 nanometers.

10. A light emitting diode according to claim 1 having a radiant flux of at least 15 milliwatts at its dominant wavelength between 524 and 527 nanometers.

11. A light emitting diode according to claim 3 including at least one buffer layer on said silicon carbide substrate, said buffer being formed from the Group III nitride material system.

12. A light emitting diode according to claim 11 including at least two layers of opposite conductivity type formed from the Group III nitride material system for providing carriers for recombination and light emission under an applied current.

13. A light emitting diode according to claim 12 wherein said light emitting structure includes at least one layer of indium gallium nitride.

14. A light emitting diode according to claim 3 comprising respective ohmic contacts to said silicon carbide substrate and to said Group III nitride light emitting structure.

15. A light emitting diode according to claim 3 wherein said silicon carbide substrate is n-type and has a polytype selected from the 3C, 4H, 6H, and 15R polytypes of silicon carbide.

16. A light emitting diode according to claim 1 having an area greater than 150,000 square microns.

17. A light emitting diode according to claim 1 having an area greater than 175,000 square microns.

18. A light emitting diode according to claim 1 having a forward voltage less than 3.1 volts.

19. A light emitting diode according to claim 1 having a forward voltage of 3.0 volts or less.

20. A light emitting diode according to claim 1 having an area between about 100,000 and about 200,000 square microns.

21. A light emitting diode having an area of at least 100,000 square microns and an external quantum efficiency greater than 50 percent at 20 milliamps current at its dominant wavelength between 390 and 540 nanometers.

22. A light emitting diode according to claim 21 having an external quantum efficiency of at least 53% at its dominant wavelength between 450 and 460 nm.

23. A light emitting diode according to claim 21 having an external quantum efficiency of t least 57% at its dominant wavelength of 453 nm.

24. A light emitting diode according to claim 21 comprising a light emitting structure formed from the Group III nitride material system.

25. A light emitting diode according to claim 24 comprising a silicon carbide single crystal substrate.

26. A light emitting diode according to claim 21 having at least one side that is at least 400 microns in length.

27. A light emitting diode according to claim 21 having its dominant wavelength between 440 and 470 nanometers.

28. A light emitting diode according to claim 21 having an external quantum efficiency greater than 30 percent at a dominant wavelength between 520 and 540 nanometers.

29. A light emitting diode according to claim 21 having an external quantum efficiency greater than 30 percent at a dominant wavelength between 520 and 530 nanometers.

30. A light emitting diode according to claim 21 having an external quantum efficiency greater than 32 percent at a dominant wavelength between 524 and 535 nanometers.

31. A light emitting diode according to claim 21 having an external quantum efficiency greater than 33 percent at a dominant wavelength between 524 and 527 nanometers.

32. A light emitting diode according to claim 25 including at least one buffer layer on said silicon carbide substrate, said buffer being formed from the Group III nitride material system.

33. A light emitting diode according to claim 32 including at least two layers of opposite conductivity type formed from the Group III nitride material system for providing carriers for recombination and light emission under an applied current.

34. A light emitting diode according to claim 33 wherein said light emitting structure includes at least one layer of indium gallium nitride.

35. A light emitting diode according to claim 25 comprising respective ohmic contacts to said silicon carbide substrate and to said Group III nitride light emitting structure.

36. A light emitting diode according to claim 25 wherein said silicon carbide substrate is n-type and has a polytype selected from the 3C, 4H, 6H, and 15R polytypes of silicon carbide.

37. A light emitting diode according to claim 21 having an area greater than 150,000 square microns.

38. A light emitting diode according to claim 21 having an area greater than 175,000 square microns.

39. A light emitting diode according to claim 21 having an area between about 100,000 and about 200,000 square microns.

40. A light emitting diode according to claim 21 having a forward voltage less than 3.1 volts.

41. A light emitting diode according to claim 21 having a forward voltage of 3.0 volts or less.

42. A light emitting diode having and an area of at least 100,000 square microns and an optical power efficiency of at least 50 percent at a dominant wavelength between 450 and 460 nanometers.

43. A light emitting diode according to claim 42 comprising a light emitting structure formed from the Group III nitride material system.

44. A light emitting diode according to claim 43 comprising a silicon carbide single crystal substrate.

45. A light emitting diode according to claim 42 having at least one side that is at least 400 microns in length.

46. A light emitting diode according to claim 42 having an optical power efficiency greater than 20 percent at a dominant wavelength between 520 and 540 nanometers.

47. A light emitting diode according to claim 42 having an optical power efficiency greater than 21 percent at a dominant wavelength between 524 and 535 nanometers.

48. A light emitting diode according to claim 42 having an optical power efficiency greater than 23 percent at a dominant wavelength between 524 and 527 nanometers.

49. A light emitting diode according to claim 44 including at least one buffer layer on said silicon carbide substrate, said buffer being formed from the Group III nitride material system.

50. A light emitting diode according to claim 49 including at least two layers of opposite conductivity type formed from the Group III nitride material system for providing carriers for recombination and light emission under an applied current.

51. A light emitting diode according to claim 50 wherein said light emitting structure includes at least one layer of indium gallium nitride.

52. A light emitting diode according to claim 44 comprising respective ohmic contacts to said silicon carbide substrate and to said Group III nitride light emitting structure.

53. A light emitting diode according to claim 44 wherein said silicon carbide substrate is n-type and has a polytype selected from the 3C, 4H, 6H, and 15R polytypes of silicon carbide.

54. A light emitting diode according to claim 42 having an area greater than 150,000 square microns.

55. A light emitting diode according to claim 42 having an area greater than 175,000 square microns.

56. A light emitting diode according to claim 42 having an area between about 100,000 and about 200,000 square microns.

57. A light emitting diode according to claim 42 having a forward voltage less than 3.1 volts.

58. A light emitting diode according to claim 42 having a forward voltage of 3.0 volts or less.

59. A light emitting diode that meets or exceeds the performance line “

A”

of FIG. 2.

60. A light emitting diode according to claim 59 that has a light emitting structure formed from the Group III nitride material system.

61. A light emitting diode according to claim 60 that is formed on a silicon carbide substrate

62. A light emitting diode according to claim 59 having an area greater than 100,000 square microns.

63. A light emitting diode according to claim 59 having at least one side that is at least 400 microns in length.

64. A light emitting diode according to claim 59 having an area greater than 175,000 square microns.

65. A light emitting diode according to claim 61 wherein said silicon carbide substrate is a single crystal having a polytype selected from the 3C, 4H, 6H, and 15R polytypes of silicon carbide.

66. A light emitting diode according to claim 61 wherein said light emitting structure includes at least two Group III nitride layers respectively doped oppositely from one another for providing carriers for recombination and light emission under an applied current.

67. A light emitting diode according to claim 66 including at least one layer of indium gallium nitride.

68. A light emitting diode according to claim 59 having a forward voltage of less than 3.1 volts at 20 milliamps current.

69. A light emitting diode according to claim 59 having a forward voltage of 3.0 volts or less at 20 milliamps current.

70. A green light emitting diode having an area of at least 100,000 square microns and a luminous efficiency greater than 100 lumens per watt.

71. A green light emitting diode according to claim 70 having a light emitting structure formed from the Group III nitride material system

72. A green light emitting diode according to claim 71 having a conductive silicon carbide substrate.

73. A green light emitting diode according to claim 70 having a dominant wave length between 520 and 540 nanometers.

74. A blue light emitting diode having an area of at least 100,000 square microns and a luminous efficiency greater than 15 lumens per watt.

75. A blue light emitting diode according to claim 74 having a dominant wavelength between 450 and 460 nanometers.