Methods of forming light emitting devices having current reducing structures

• US 8,436,368 B2
• Filed: 02/27/2012
• Issued: 05/07/2013
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Emerson, David Todd, Haberern, Kevin, Bergmann, Michael John, Slater, David B. Jr., Donofrio, Matthew, Edmond, John
• Primary Examiner(s): Smith, Zandra
• Assistant Examiner(s): PATTON, PAUL E
• Application Number:
  US13/406,251
• Publication Number:
  US 20120153343A1
• Time in Patent Office: 435 Days
• Field of Search: 257/79, 257/E33.005
• US Class Current: 257/79
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01L 33/38 with a particular shape

Abstract

A light emitting device includes a p-type semiconductor layer, an n-type semiconductor layer, and an active region between the n-type semiconductor layer and the p-type semiconductor layer. A non-transparent feature, such as a wire bond pad, is on the p-type semiconductor layer or on the n-type semiconductor layer opposite the p-type semiconductor layer, and a reduced conductivity region is in the p-type semiconductor layer or the n-type semiconductor layer and is aligned with the non-transparent feature. The reduced conductivity region may extend from a surface of the p-type semiconductor layer opposite the n-type semiconductor layer towards the active region and/or from a surface of the n-type semiconductor layer opposite the p-type semiconductor layer towards the active region.

Claims

1. A light emitting device, comprising:

a p-type semiconductor layer, an n-type semiconductor layer and an active region between the n-type semiconductor layer and the p-type semiconductor layer;

a non-transparent feature on the n-type semiconductor layer opposite the active region; and

a patterned ohmic contact on the p-type semiconductor layer opposite the active region, wherein the patterned ohmic contact is aligned with the non-transparent feature.

2. The light emitting device of claim 1, wherein the non-transparent feature comprises a bond pad and/or a passivation region.

3. The light emitting device of claim 1, wherein the non-transparent feature comprises a conductive finger.

4. The light emitting device of claim 1, further comprising a substrate between the n-type semiconductor layer and the non-transparent feature.

5. The light emitting device of claim 1, further comprising a patterned non-ohmic contact on the p-type semiconductor layer, wherein the patterned non-ohmic contact also is aligned with the non-transparent feature.

6. The light emitting device of claim 5, wherein the patterned non-ohmic contact comprises a metal that does not form an ohmic contact with the p-type semiconductor layer, or comprises an insulator.

7. The light emitting device of claim 1 wherein the light emitting device is a vertical light emitting diode.

8. A light emitting device, comprising:

a p-type semiconductor layer, an n-type semiconductor layer and an active region between the n-type semiconductor layer and the p-type semiconductor layer;

a non-transparent feature on the n-type semiconductor layer opposite the active region; and

an ohmic contact on the p-type semiconductor layer opposite the active region, wherein the ohmic contact exposes a portion of the p-type semiconductor layer that is aligned with the non-transparent feature.

9. The light emitting device of claim 8, wherein the non-transparent feature comprises a bond pad and/or a passivation region.

10. The light emitting device of claim 8, wherein the non-transparent feature comprises a conductive finger.

11. The light emitting device of claim 8, further comprising a substrate between the n-type semiconductor layer and the non-transparent feature.

12. The light emitting device of claim 8, further comprising a patterned non-ohmic contact on the portion of the p-type semiconductor layer that is exposed by the ohmic contact.

13. The light emitting device of claim 12, wherein the patterned non-ohmic contact comprises a metal that does not form an ohmic contact with the p-type semiconductor layer, or comprises an insulator.

14. The light emitting device of claim 8 wherein the light emitting device is a vertical light emitting diode.

15. A light emitting device, comprising:

a p-type semiconductor layer, an n-type semiconductor layer and an active region between the n-type semiconductor layer and the p-type semiconductor layer;

a non-transparent feature on the n-type semiconductor layer opposite the active region; and

an ohmic contact on the p-type semiconductor layer opposite the active region, wherein the ohmic contact includes an opening therein that is aligned with the non-transparent feature.

16. The light emitting device of claim 15, wherein the non-transparent feature comprises a bond pad and/or a passivation region.

17. The light emitting device of claim 15, wherein the non-transparent feature comprises a conductive finger.

18. The light emitting device of claim 15, further comprising a substrate between the n-type semiconductor layer and the non-transparent feature.

19. The light emitting device of claim 15, further comprising a non-ohmic contact in the opening.

20. The light emitting device of claim 19, wherein the non-ohmic contact comprises a metal that does not form an ohmic contact with the p-type semiconductor layer, or comprises an insulator.

21. The light emitting device of claim 15 wherein the light emitting device is a vertical light emitting diode.

22. A light emitting device, comprising:

a semiconductor diode having first and second opposing semiconductor surfaces of opposite conductivity types;

a non-transparent feature on the first semiconductor surface; and

a patterned ohmic contact on the second semiconductor surface, wherein the patterned ohmic contact is aligned with the non-transparent feature.

23. The light emitting device of claim 22, wherein the non-transparent feature comprises a bond pad and/or a passivation region.

24. The light emitting device of claim 22, wherein the non-transparent feature comprises a conductive finger.

25. The light emitting device of claim 22, further comprising a substrate between the first semiconductor surface and the non-transparent feature.

26. The light emitting device of claim 22, further comprising a patterned non-ohmic contact on the second semiconductor surface, wherein the patterned non-ohmic contact also is aligned with the non-transparent feature.

27. The light emitting device of claim 26, wherein the patterned non-ohmic contact comprises a metal that does not form an ohmic contact with the second semiconductor surface, or comprises an insulator.

28. The light emitting device of claim 22 wherein the light emitting device is a vertical light emitting diode.

29. A light emitting device, comprising:

a semiconductor diode having first and second opposing semiconductor surfaces of opposite conductivity types;

a non-transparent feature on the first semiconductor surface; and

an ohmic contact on the second semiconductor surface, wherein the ohmic contact exposes a portion of the second semiconductor surface that is aligned with the non-transparent feature.

30. The light emitting device of claim 29, wherein the non-transparent feature comprises a bond pad and/or a passivation region.

31. The light emitting device of claim 29, wherein the non-transparent feature comprises a conductive finger.

32. The light emitting device of claim 29, further comprising a substrate between the first semiconductor surface and the non-transparent feature.

33. The light emitting device of claim 29, further comprising a patterned non-ohmic contact on the portion of the second semiconductor surface that is exposed by the ohmic contact.

34. The light emitting device of claim 33, wherein the patterned non-ohmic contact comprises a metal that does not form an ohmic contact with the second semiconductor surface, or comprises an insulator.

35. The light emitting device of claim 29 wherein the light emitting device is a vertical light emitting diode.

36. A light emitting device, comprising:

a semiconductor diode having first and second opposing semiconductor surfaces of opposite conductivity types;

a non-transparent feature on the first semiconductor surface; and

an ohmic contact on the second semiconductor surface, wherein the ohmic contact includes an opening therein that is aligned with the non-transparent feature.

37. The light emitting device of claim 36, wherein the non-transparent feature comprises a bond pad and/or a passivation region.

38. The light emitting device of claim 36, wherein the non-transparent feature comprises a conductive finger.

39. The light emitting device of claim 36, further comprising a substrate between the first semiconductor surface and the non-transparent feature.

40. The light emitting device of claim 36, further comprising a non-ohmic contact in the opening.

41. The light emitting device of claim 40, wherein the non-ohmic contact comprises a metal that does not form an ohmic contact with the p-type semiconductor layer, or comprises an insulator.

42. The light emitting device of claim 36 wherein the light emitting device is a vertical light emitting diode.

43. A light emitting device, comprising:

a p-type semiconductor layer, an n-type semiconductor layer and an active region between the n-type semiconductor layer and the p-type semiconductor layer;

a conductive finger on the n-type semiconductor layer opposite the active region; and

a patterned ohmic contact on the p-type semiconductor layer opposite the active region, wherein the patterned ohmic contact is aligned with the conductive finger.

44. The light emitting device of claim 43, further comprising a substrate between the n-type semiconductor layer and the conductive finger.

45. The light emitting device of claim 43, further comprising a patterned non-ohmic contact on the p-type semiconductor layer, wherein the patterned non-ohmic contact also is aligned with the conductive finger.

46. The light emitting device of claim 45, wherein the patterned non-ohmic contact comprises a metal that does not form an ohmic contact with the p-type semiconductor layer, or comprises an insulator.

47. The light emitting device of claim 43 wherein the light emitting device is a vertical light emitting diode.

48. A method of fabricating a light emitting device, comprising:

forming a p-type semiconductor layer, an n-type semiconductor layer and an active region between the n-type semiconductor layer and the p-type semiconductor layer;

forming a non-transparent feature on the n-type semiconductor layer opposite the active region; and

forming a patterned ohmic contact on the p-type semiconductor layer opposite the active region, wherein the patterned ohmic contact is aligned with the non-transparent feature.

49. The method of claim 48, wherein forming the non-transparent feature comprises forming a bond pad and/or a passivation region.

50. The method of claim 48, wherein forming the non-transparent feature comprises forming a conductive finger.

51. The method of claim 48, further comprising forming a substrate between the n-type semiconductor layer and the non-transparent feature.

52. The method of claim 48, further comprising forming a patterned non-ohmic contact on the p-type semiconductor layer, wherein the patterned non-ohmic contact also is aligned with the non-transparent feature.

53. The method of claim 52, wherein forming the patterned non-ohmic contact comprises forming a metal that does not form an ohmic contact with the p-type semiconductor layer, or forming an insulator.

54. The method of claim 48 wherein the light emitting device is a vertical light emitting diode.