CONTACT FOR A SEMICONDUCTOR LIGHT EMITTING DEVICE

• US 20120199863A1
• Filed: 04/17/2012
• Published: 08/09/2012
• Est. Priority Date: 06/25/2009
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Epler, John E., David, Aurelien J.F.
• Granted Patent: US 11,695,099 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials

Abstract

Embodiments of the invention include a semiconductor structure comprising a III-nitride light emitting layer disposed between an n-type region and a p-type region. A contact disposed on the p-type region includes a transparent conductive material in direct contact with the p-type region, a reflective metal layer, and a transparent insulating material disposed between the transparent conductive layer and the reflective metal layer. In a plurality of openings in the transparent insulating material, the transparent conductive material is in direct contact with the reflective metal layer.

Claims

1-17. -17. (canceled)

18. A device comprising:

a semiconductor structure that includes a light emitting layer disposed between an n-type region and a p-type region; and

a contact that is disposed on the p-type region and includes;

a transparent conductive material in direct contact with the p-type region;

a reflective metal layer;

a transparent insulating material disposed between the transparent conductive layer and the reflective metal layer; and

a plurality of openings in the transparent insulating material, wherein the transparent conductive material is in direct contact with the reflective metal layer in the plurality of openings;

wherein the contact includes one or more features that serve to provide a scattering of light emitted by the light emitting layer.

19. The device of claim 18, wherein the one or more features include a roughened surface of the p-type region.

20. The device of claim 18, wherein the one or more features include a porous composition of the transparent conductive material.

21. The device of claim 18, wherein the one or more features include a porous composition of the transparent insulating material.

22. The device of claim 18, wherein the one or more features include a multi-layer composition of the transparent insulating material.

23. The device of claim 22, wherein the multi-layer composition includes layers having different indices of refraction, the index of refraction of at least one inner layer being substantially less than an index of refraction of a layer that is adhered to one of:

the transparent conductive layer and the reflective metal layer.

24. The device of claim 18, wherein the one or more features include sloped walls forming the openings.

25. The device of claim 18, wherein the sloped walls are sloped at an angle between five and fifty degrees relative to a direction that is normal to a surface of the transparent conductive material.

26. The device of claim 18, wherein the one or more features include one or more of the openings extending into the transparent conductive material.

27. The device of claim 18, wherein the transparent conductive material includes annealed silver.

28. A method comprising:

forming a semiconductor structure that includes a light emitting layer disposed between an n-type region and a p-type region; and

forming a contact on the p-type region, the contact including;

a transparent conductive material in direct contact with the p-type region;

a reflective metal layer; and

a transparent insulating material disposed between the transparent conductive material and the reflective metal layer; and

a plurality of openings in the transparent insulating material, wherein the transparent conductive material is in direct contact with the reflective metal layer in the plurality of openings;

wherein forming the contact includes forming one or more features that serve to provide a scattering of light emitted by the light emitting layer.

29. The method of claim 28, wherein forming the contact includes growing the p-type region under conditions that result in a substantially roughened surface on the p-type region.

30. The method of claim 29, wherein forming the contact includes applying an Al-doped ZnO layer to the roughened surface to form the transparent conductive material, and spin coating a low index SiO_x layer over the Al-doped ZnO layer to form the transparent insulating material.

31. The method of claim 28, wherein forming the contact includes forming the transparent conductive material by oblique angle deposition.

32. The method of claim 28, wherein forming the contact includes forming the transparent insulating material by oblique angle deposition.

33. The method of claim 28, wherein forming the contact includes forming the transparent insulating material as a multi-layer structure.

34. The method of claim 28, wherein the multi-layer structure includes layers having different indices of refraction, the index of refraction of at least one inner layer being substantially less than an index of refraction of a layer that is adhered to one of:

the transparent conductive layer and the reflective metal layer.

35. The method of claim 28, wherein forming the contact includes forming the openings with walls that are sloped at an angle between five and fifty degrees relative to a direction that is normal to a surface of the transparent conductive material.

36. The method of claim 28, wherein the one or more features include one or more of the openings extending into the transparent conductive material.

37. The method of claim 28, wherein forming the contact includes annealing a layer of silver that is evaporated onto the p-type region to form the transparent conductive material.