Light emitting devices having current blocking structures and methods of fabricating light emitting devices having current blocking structures

• US 20060002442A1
• Filed: 06/30/2004
• Published: 01/05/2006
• Est. Priority Date: 06/30/2004
• Status: Abandoned Application

• Current Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Bergmann, Michael John, Emerson, David Todd, Haberern, Kevin, Mieczkowski, Van
• Application Number:
  US10/881,814
• Publication Number:
  US 20060002442A1
• Time in Patent Office: Days
• US Class Current: 372/46.10
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01S 5/0421 characterised by the semiconducting contacting layers electrodes H01S5/0425
• CPC Class Codes: H01S 5/2063 obtained by particle bombardment
• CPC Class Codes: H01S 5/2068 obtained by radiation treatment or annealing
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

Light emitting devices and methods of fabricating light emitting devices having a current blocking mechanism below the wire bond pad are provided. The current blocking mechanism may be a reduced conduction region in an active region of the device. The current blocking mechanism could be a damage region of a layer on which a contact is formed. The current blocking mechanism could be a Schottky contact between an ohmic contact and the active region of the device. A semiconductor junction, such as a PN junction could also be provided between the ohmic contact and the active region.

Claims

1. A light emitting device, comprising:

an active region of semiconductor material;

a first contact on the active region, the first contact having a bond pad region thereon;

a reduced conduction region disposed in the active region beneath the bond pad region of the first contact and configured to reduce current flow through the active region in the region beneath the bond pad region of the first contact; and

a second contact electrically coupled to the active region.

2. The light emitting device of claim 1, wherein the reduced conduction region extends from the first contact to the active region.

3. The light emitting device of claim 1, wherein the reduced conduction region extends from the first contact into the active region.

4. The light emitting device of claim 1, wherein the reduced conduction region extends from the first contact through the active region.

5. The light emitting device of claim 1, wherein the reduced conduction region extends through the active region.

6. The light emitting device of claim 1, further comprising a p-type semiconductor material disposed between the first contact and the active region;

and

wherein the reduced conduction region extends from the first contact, through the p-type semiconductor material and through the active region.

7. The light emitting device of claim 1, wherein the active region comprises a Group III-nitride based active region.

8. The light emitting device of claim 1, further comprising a bond pad on the first contact in the bond pad region.

9. The light emitting device of claim 8, wherein the reduced conduction region is self-aligned with the bond pad.

10. The light emitting device of claim 1, wherein the reduced conduction region comprises an insulating region.

11. The light emitting device of claim 10, wherein the reduced conduction region comprises a region that is not light absorbing.

12. The light emitting device of claim 10, wherein the reduced conduction regions comprises an implanted region.

13. A light emitting device, comprising:

a Group III-nitride based active region;

a first contact directly on a Group III-nitride based layer on the active region, the first contact having a first portion that makes ohmic contact to the Group III-nitride based layer and a second portion that does not make ohmic contact to the Group III-nitride based layer, the second portion corresponding to a bond pad region of the first contact; and

a second contact electrically coupled to the active region.

14. The light emitting device of claim 13, wherein the second portion corresponds to a region of damage at an interface between the Group III-nitride based layer and the first contact.

15. The light emitting device of claim 14, wherein the region of damage comprises a wet or dry etched region of the Group III-nitride based layer.

16. The light emitting device of claim 14, wherein the region of damage comprises a region of the Group III-nitride based layer and/or first contact exposed to a high energy plasma.

17. The light emitting device of claim 14, wherein the region of damage comprises a region of the Group III-nitride based layer exposed to a H₂.

18. The light emitting device of claim 14, wherein the region of damage comprises a region of the Group III-nitride based layer exposed to a high energy laser.

19. The light emitting device of claim 13, further comprising a wire bond pad on the bond pad region of the first contact.

20. The light emitting device of claim 13, wherein the first contact comprises a layer of platinum.

21. The light emitting device of claim 20, wherein the layer of platinum is substantially transparent.

22. The light emitting device of claim 14, further comprising a wire bond pad on the bond pad region of the first contact, and wherein the region of damage and the wire bond pad are self-aligned.

23. A light emitting device, comprising:

an active region of semiconductor material;

a Schottky contact on the active region;

a first ohmic contact on the active region and the Schottky contact, a portion of the first ohmic contact on the Schottky contact corresponding to a bond pad region of the first ohmic contact; and

a second ohmic contact electrically coupled to the active region.

24. The light emitting device of claim 23, further comprising a bond pad on the bond pad region of the first ohmic contact.

25. The light emitting device of claim 23, wherein the active region comprises a Group III-nitride based active region.

26. A light emitting device, comprising:

an active region of semiconductor material;

a first ohmic contact on the active region, a portion of the first ohmic contact directly on a region of semiconductor material of a first conductivity type and a second portion of the first ohmic contact directly on a region of semiconductor material of a second conductivity type opposite the first conductivity type, the second portion corresponding to a bond pad region of the first ohmic contact; and

a second ohmic contact electrically coupled to the active region.

27. The light emitting device of claim 26, wherein the region of semiconductor material of the second conductivity type comprises a layer of second conductivity type semiconductor material.

28. The light emitting device of claim 26, wherein region of semiconductor material of the first conductivity type comprises a layer of semiconductor material of the first conductivity type and wherein the region of semiconductor material of the second conductivity type is disposed with the layer of semiconductor material of the first conductivity type.

29. The light emitting device of claim 26, wherein the active region comprises a Group III-nitride based active region.

30. The light emitting device of claim 26, further comprising a bond pad on the bond pad region of the first ohmic contact.

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

forming an active region of semiconductor material;

forming a first contact on the active region, the first contact having a bond pad region thereon;

forming a reduced conduction region disposed in the active region beneath the bond pad region of the first contact and configured to block current flow through the active region in the region beneath the bond pad region of the first contact; and

forming a second contact electrically coupled to the active region.

32. The method of claim 31, wherein the reduced conduction region extends from the first contact to the active region.

33. The method of claim 31, wherein the reduced conduction region extends from the first contact into the active region.

34. The method of claim 31, wherein the reduced conduction region extends from the first contact through the active region.

35. The method of claim 31, wherein the reduced conduction region extends through the active region.

36. The method of claim 31, further comprising forming a p-type semiconductor material disposed between the first contact and the active region;

and

wherein the reduced conduction region extends from the first contact, through the p-type semiconductor material and through the active region.

37. The method of claim 31, wherein the active region comprises a Group III-nitride based active region.

38. The method of claim 31, further comprising forming a bond pad on the first contact in the bond pad region.

39. The method of claim 38, wherein the reduced conduction region is self-aligned with the bond pad.

40. The method of claim 31, wherein forming a reduced conduction region comprises:

forming a mask layer on the first ohmic contact, the mask layer having an opening corresponding to the bond pad region; and

implanting atoms in the active region through the opening in the mask layer.

41. The method of claim 40, further comprising forming a bond pad in the opening in the mask layer.

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

forming a Group III-nitride based active region;

forming a first contact directly on a Group III-nitride based layer on the active region, the first contact having a first portion that makes ohmic contact to the Group III-nitride based layer and a second portion that does not make ohmic contact to the Group III-nitride based layer, the second portion corresponding to a bond pad region of the first contact; and

forming a second contact electrically coupled to the active region.

43. The method of claim 42, wherein forming a first contact comprises damaging a region of the Group III-nitride based layer corresponding to the second portion of the first contact.

44. The method of claim 43, wherein damaging a region comprises wet or dry etching the region of the Group III-nitride based layer.

45. The method of claim 43, wherein damaging a region comprises exposing the region of the Group III-nitride based layer and/or first contact to high energy plasma.

46. The method of claim 43, wherein damaging a region comprises exposing the region of the Group III-nitride based layer to H₂.

47. The method of claim 43, wherein damaging a region comprises exposing the region of the Group III-nitride based layer to a high energy laser.

48. The method of claim 42, further comprising forming a wire bond pad on the bond pad region of the first contact.

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

forming an active region of semiconductor material;

forming a Schottky contact on the active region;

forming a first ohmic contact on the active region and the Schottky contact, a portion of the first ohmic contact on the Schottky contact corresponding to a bond pad region of the first ohmic contact; and

forming a second ohmic contact electrically coupled to the active region.

50. The method of claim 49, further comprising forming a bond pad on the bond pad region of the first ohmic contact.

51. The method of claim 49, wherein the active region comprises a Group III-nitride based active region.

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

forming an active region of semiconductor material;

forming a first ohmic contact on the active region, a portion of the first ohmic contact is directly on a region of semiconductor material of a first conductivity type and a second portion of the first ohmic contact is directly on a region of semiconductor material of a second conductivity type opposite the first conductivity type, the second portion corresponding to a bond pad region of the first ohmic contact; and

forming a second ohmic contact electrically coupled to the active region.

53. The method of claim 52, wherein the region of semiconductor material of the second conductivity type comprises a layer of second conductivity type semiconductor material.

54. The method of claim 52, wherein region of semiconductor material of the first conductivity type comprises a layer of semiconductor material of the first conductivity type and wherein the region of semiconductor material of the second conductivity type is disposed with the layer of semiconductor material of the first conductivity type.

55. The method of claim 52, wherein the active region comprises a Group III-nitride based active region.

56. The method of claim 52, further comprising forming a bond pad on the bond pad region of the first ohmic contact.