LIGHT EMITTING DIODES WITH PATTERNED CURRENT BLOCKING METAL CONTACT

• US 20090242929A1
• Filed: 05/01/2008
• Published: 10/01/2009
• Est. Priority Date: 03/31/2008
• Status: Abandoned Application

• Current Assignee: Bridgelux Incorporated
• Original Assignee: Bridgelux Incorporated
• Inventors: LIN, Chao-Kun
• Application Number:
  US12/113,556
• Publication Number:
  US 20090242929A1
• Time in Patent Office: Days
• US Class Current: 257/103
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/145 with a current-blocking structure

Abstract

A light emitting diode including an epitaxial layer structure, a first electrode formed on the epitaxial layer structure, and a second electrode formed on the epitaxial layer structure. The first electrode has a pattern and the second electrode has a portion aligned with the pattern of the first electrode. The portion of the second electrode forms a non-ohmic contact with the epitaxial layer structure.

Claims

1. A light emitting diode, comprising:

an epitaxial layer structure;

a first electrode formed on the epitaxial layer structure, the first electrode having a pattern; and

a second electrode formed on the epitaxial layer structure, the second electrode having a portion aligned with the pattern of the first electrode,

wherein the portion of the second electrode forms a non-ohmic contact with the epitaxial layer structure.

2. The light emitting diode of claim 1, wherein the epitaxial layer structure comprises first and second epitaxial layers, wherein the first epitaxial layer is between the first electrode and the second epitaxial layer, and the second epitaxial layer is between the second electrode and the first epitaxial layer.

3. The light emitting diode of claim 2, further comprising an active region between the first and second epitaxial layers.

4. The light emitting diode of claim 2, wherein the non-ohmic contact portion exists between the second electrode and the second epitaxial layer.

5. The light emitting diode of claim 2, wherein the non-ohmic contact portion has a Schottky contact with the second epitaxial layer.

6. The light emitting diode of claim 2, wherein the non-ohmic contact portion is formed via a plasma treatment on the second epitaxial layer.

7. The light emitting diode of claim 2, wherein the non-ohmic contact portion is formed by photo-resisting the second epitaxial layer and plasma-treating the photoresisted epitaxial layer so that the non-ohmic contact portion is formed between the second electrode and the second epitaxial layer where the second epitaxial layer is not covered by a photo-resist.

8. The light emitting-diode of claim 7, wherein the plasma treatment uses a gas including O₂, N₂, H₂, Ar, He, Ne, Kr, Xe, or any combination thereof.

9. The light emitting diode of claim 7, wherein the non-ohmic contact portion includes a metal selected from Ag, Pt, Ni, Cr, Ti, Al, Cu, Pd, W, Ru, Rh, Mo, and their alloys.

10. The light emitting diode of claim 7, wherein the plasma treatment compensates a doping concentration near a surface of the second epitaxial layer.

11. The light emitting diode of claim 7, wherein the plasma treatment converts a doping of the second eptiaxial layer at areas treated by the plasma treatment into an opposite doping.

12. The emitting diode of claim 1, wherein a width of the pattern of the non-ohmic contact portion is equal to or greater than a width of the pattern of the first electrode.

13. The light emitting diode of claim 1, wherein the second electrode comprises a metal selected from Ag, Pt, Ni, Cr, Ti, Al, Cu, Pd, W, Ru, Rh, Mo, and their alloys.

14. The light emitting diode of claim 1, wherein the second electrode layer comprises first and second materials, wherein the second material forms the non-ohmic contact portion with the epitaxial layer structure.

15. The light emitting diode of claim 14, wherein the first material includes a metal selected from Ag, Pt, Ni, Cr, Ti, Al, Cu, Pd, W, Ru, Rh, Mo, and their alloys.

16. The light emitting diode of claim 14, wherein the first material is formed partially on the epitaxial layer structure and areas on the epitaxial layer structure without the first material forms a pattern aligned with that pattern of the first electrode, wherein the second material is formed on the first material.

17. The light emitting diode of claim 1, wherein the second electrode is attached to a substrate.

18. The light emitting diode of claim 17, wherein the substrate is selected from a group consisting of a metal, a semiconductor material, and a ceramic.

19. The light emitting diode of claim 18, wherein the metal includes one selected from Cu, Mo, W, and Al, the semiconductor includes one selected from Si, GaAs, GaP, InP, and Ge, and the ceramic includes one selected from Al₂O₃ and AlN.

20. A method for manufacturing a light emitting diode, comprising:

forming an epitaxial layer structure;

forming a first electrode, the first electrode having a first pattern on the epitaxial layer structure; and

forming a second electrode on the epitaxial layer structure,

wherein the second electrode is formed with a portion aligned with the pattern of the first electrode, the portion of the second electrode forming a non-ohmic contact with the epitaxial layer structure.

21. The method of claim 20, wherein the epitaxial layer structure comprises a first epitaxial layer and a second epitaxial layer, wherein the first electrode is formed on the first epitaxial layer and the second electrode is formed on the second epitaxial layer.

22. The method of claim 21, further comprising forming an active region between the first and second epitaxial layers.

23. The method of claim 21, wherein the non-ohmic contact portion is formed via a plasma treatment on the second epitaxial layer.

24. The method of claim 21, wherein the non-ohmic contact portion is formed by photo-resisting the second epitaxial layer and plasma-treating the photoresisted epitaxial layer so that the non-ohmic contact portion is formed between the second electrode and the second epitaxial layer where the second epitaxial layer is not covered by a photo-resist.

25. The method of claim 24, wherein the plasma treatment uses gases including O₂, N₂, H₂, Ar, He, Ne, Kr, Xe, or their mixture.

26. The method of claim 24, wherein the plasma treatment compensates a doping concentration near a surface of the second epitaxial layer that are not covered by a photo-resist layer.

27. The method of claim 24, wherein the plasma treatment converts a doping of the second epitaxial layer at areas treated by the plasma treatment into an opposite doping.

28. The method of claim 20, wherein a width of the pattern of the non-ohmic contact portion is equal to or greater than a width of the pattern of the first electrode.

29. The method of claim 20, wherein the second electrode is formed by depositing a metal selected from Ag, Pt, Ni, Cr, Ti, Al, Cu, Pd, W, Ru, Rh, Mo, and their alloys.

30. The method of claim 21, wherein the forming of the epitaxial layer structure comprises forming the first epitaxial layer on a substrate, and removing the substrate, and wherein the first electrode is formed on a surface of the first epitaxial layer that was attached to the substrate.

31. The method of claim 30, wherein the substrate is sapphire (Al₂O₃) or silicon carbide (SiC).

32. The method of claim 20, further comprising attaching the second electrode to a substrate.

33. The method of claim 32, wherein the substrate is selected from a group consisting of a metal, a semiconductor material, and a ceramic.

34. The method of claim 33, wherein the metal includes one selected from Cu, Mo, W, and Al, the semiconductor material includes one selected from Si, GaAs, GaP, InP, and Ge, and the ceramic includes one selected from Al₂O₃ and AlN.

35. The method of claim 20, wherein forming of the second electrode comprises patterning a first material with a pattern opposite parity to the pattern of the first electrode, and arranging a second material with the first material, the non-ohmic contact portion being between the second material and the epitaxial layer structure.

36. The method of claim 35, wherein the first material is formed on the epitaxial layer structure, and is etched to form a pattern that are aligned with the pattern of the first electrode, wherein the second material is deposited on the first material after the etching process and is in touch with the epitaxial layer structure.

37. The method of claim 35, wherein the non-ohmic contact portion is formed by depositing a metal selected from Ag, Pt, Ni, Cr, Ti, Al, Cu, Pd, W, Ru, Rh, Mo, and their alloys.