CONTACT FOR A SEMICONDUCTOR LIGHT EMITTING DEVICE

• US 20100327300A1
• Filed: 06/25/2009
• Published: 12/30/2010
• Est. Priority Date: 06/25/2009
• Status: Abandoned Application

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.), Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: DAVID, Aurelien J.F., EPLER, John E.
• Application Number:
  US12/491,976
• Publication Number:
  US 20100327300A1
• 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. A device comprising:

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, the contact comprising;

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

a reflective metal layer;

an 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.

2. The device of claim 1 wherein the transparent conductive material is one of silver and aluminum.

3. The device of claim 2 wherein the transparent conductive material comprises a plurality of discrete regions that occupy less than 10% of an area of a surface of the p-type region on which the contact is disposed.

4. The device of claim 1 wherein the transparent conductive material has a thickness between 0.5 and 10 nanometers.

5. The device of claim 1 wherein the transparent conductive material is an oxide and has a thickness between 30 and 1000 nanometers.

6. The device of claim 1 wherein the transparent conductive material is one of indium tin oxide, nickel oxide, and ZnO.

7. The device of claim 1 wherein the transparent insulating material is one of SiO_x, SiN_x, MgF₂, and Al₂O₃.

8. The device of claim 1 wherein the transparent insulating material has a thickness between 200 and 500 nm.

9. The device of claim 1 wherein the openings have a width between two and fifteen microns.

10. The device of claim 1 wherein the openings are spaced between 20 and 200 microns apart.

11. The device of claim 1 wherein the transparent insulating material comprises a multi-layer stack.

12. The device of claim 11 wherein:

a first layer in the multi-layer stack is in direct contact with the transparent conductive material;

a second layer in the multi-layer stack is in direct contact with the reflective metal layer; and

a third layer disposed between the first and second layers has a lower index of refraction than the first and second layers.

13. The device of claim 1 wherein the reflective metal layer comprises silver.

14. The device of claim 1 wherein a surface of the p-type region in direct contact with the transparent conductive material is rough.

15. The device of claim 1 wherein the openings extend into the transparent conductive material.

16. The device of claim 1 wherein the openings have a sidewall angle between 5 and 50 degrees with respect to a normal to a top surface of the reflective metal layer.

17. The device of claim 1 wherein at least one of the transparent insulating material and the transparent conductive material is porous.