Method of forming ohmic contact layer and method of fabricating light emitting device having ohmic contact layer

• US 20060270206A1
• Filed: 05/18/2006
• Published: 11/30/2006
• Est. Priority Date: 05/18/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Seong, Tae-yeon, Leem, Dong-seok, Cho, Jae-hee, Sone, Cheol-soo
• Granted Patent: US 8,580,668 B2
• Time in Patent Office: Days
• US Class Current: 438/597
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/42 Transparent materials

Abstract

A method of manufacturing an ohmic contact layer and a method of manufacturing a top emission type nitride-based light emitting device having the ohmic contact layer are provided. The method of manufacturing an ohmic contact layer includes: forming a first conductive material layer on a semiconductor layer; forming a mask layer having a plurality of nano-sized islands on the first conductive material layer; forming a second conductive material layer on the first conductive material layer and the mask layer; and removing the portion of the second conductive material on the islands and the islands through a lift-off process using a solvent. The method ensures the maintenance of good electrical characteristics and an increase of the light extraction efficiency.

Claims

1. A method of manufacturing an ohmic contact layer which is used for a light emitting device and comprises a first conductive material layer and a second conductive material layer having through-holes corresponding to islands, the method comprising:

forming a first conductive material layer on a semiconductor layer;

forming a mask layer comprising a plurality of nano-sized islands on the first conductive material layer;

forming a second conductive material layer on the first conductive material layer and on the islands in the mask layer; and

removing the portion of the second conductive material on the islands through a lift-off process using a solvent.

2. The method of claim 1, wherein the first and second conductive material layers are formed of transparent conductive oxide or transparent conductive nitride.

3. The method of claim 2, wherein the transparent conductive oxide comprises at least one metal oxide and the metal is selected from the group consisting of In, Sn, Zn, Ga, Ce, Cd, Mg, Be, Ag, Mo, V, Cu, Ir, Rh, Ru, W, Co, Ni, Mn, Al, and lanthanide metals.

4. The method of claim 2, wherein the transparent conductive nitride is titanium nitride or tantalum nitride.

5. The method of claim 1, further comprising, before the forming of the first conductive material layer, forming a metal thin film layer on the semiconductor layer, wherein the first conductive material layer is formed on the metal thin film layer.

6. The method of claim 5, wherein the metal thin film layer has a thickness of approximately 0.1 to 50 nm.

7. The method of claim 6, wherein the metal thin film layer is formed of a material selected from the group consisting of Ni, Co, Cu, Pd, Pt, Ru, Ir, Au, Ag, Cr, Rh, In, Sn, Mg, Zn, Be, Sr, Ba, an alloy thereof, and a solid solution thereof.

8. The method of claim 5, wherein the metal thin film layer is formed of a material selected from the group consisting of Ni, Co, Cu, Pd, Pt, Ru, Ir, Au, Ag, Cr, Rh, In, Sn, Mg, Zn, Be, Sr, Ba, an alloy thereof, and a solid solution thereof.

9. The method of claim 1, wherein the forming of the mask layer comprises:

coating a photoresist on the first conductive material layer;

exposing the photoresist to form a latent image corresponding to the islands in the photoresist; and

forming the islands on the first conductive material layer by developing the photoresist using a solvent.

10. The method of claim 9, wherein the exposing of the photoresist is performed through laser holography using laser interference.

11. The method of claim 9, wherein the exposing of the photoresist is performed though electron beam lithography.

12. The method of claim 1, wherein the exposing of the photoresist is performed though laser holography using laser interference.

13. The method of claim 1, wherein the exposing of the photoresist is performed through electron beam lithography.

14. A method of manufacturing an ohmic contact layer which is used for a light emitting device and comprises a first conductive material layer and a second conductive material layer having through-holes corresponding to islands, the method comprising:

forming a stacked structure comprising a first clading semiconductor layer, an activation layer, and an second clading semiconductor layer on a substrate;

forming a first conductive material layer the second cladding semiconductor layer;

forming a mask layer comprising a plurality of islands on the first conductive material layer;

forming a second conductive material layer on the first conductive material layer and on the islands in the mask layer; and

removing the portion of the second conductive material on the islands and the islands through a lift-off process using a solvent.

15. The method of claim 14, wherein the first and second conductive material layers are formed of a transparent conductive oxide or transparent conductive nitride.

16. The method of claim 15, wherein the transparent conductive oxide comprises at least one metal oxide and the metal is selected from the group consisting of In, Sn, Zn, Ga, Ce, Cd, Mg, Be, Ag, Mo, V, Cu, Ir, Rh, Ru, W, Co, Ni, Mn, Al, and lanthanide metals.

17. The method of claim 15, wherein the transparent conductive nitride is titanium nitride or tantalum nitride.

18. The method of claim 14, further comprising, before the forming of the first conductive material layer, forming a metal thin film layer on the semiconductor layer, wherein the first conductive material layer is formed on the metal thin film layer.

19. The method of claim 18, wherein the metal thin film layer has a thickness of approximately 0.1 to 50 nm.

20. The method of claim 19, wherein the metal thin film layer is formed of a material selected from the group consisting of Ni, Co, Cu, Pd, Pt, Ru, Ir, Au, Ag, Cr, Rh, In, Sn, Mg, Zn, Be, Sr, Ba, an alloy thereof, and a solid solution thereof.

21. The method of claim 18, wherein the metal thin film layer is formed of a material selected from the group consisting of Ni, Co, Cu, Pd, Pt, Ru, Ir, Au, Ag, Cr, Rh, In, Sn, Mg, Zn, Be, Sr, Ba, an alloy thereof, and a solid solution thereof.

22. The method of claim 14, wherein the forming of the mask layer comprises:

coating a photoresist on the first conductive material layer;

exposing the photoresist to form a latent image corresponding to the islands in the photoresist; and

forming the islands on the first conductive material layer by developing the photoresist using a solvent.

23. The method of claim 22, wherein the exposing of the photoresist is performed through laser holography using laser interference.

24. The method of claim 22, wherein the exposing of the photoresist is performed through electron beam lithography.

25. The method of claim 14, wherein the exposing of the photoresist is performed through laser holography using laser interference.

26. The method of claim 14, wherein the exposing of the photoresist is performed through electron beam lithography.

27. The method of claim 14, wherein the first conductive material layer has a thickness of approximately 0.1 to 300 nm, and the second conductive material layer has a thickness of approximately 20 to 700 nm.

28. The method of claim 14, wherein the first conductive material and the second conductive material in which the through holes are formed form an electrode, the method further comprising:

heat-treating the electrode at a temperature ranging from room temperature to approximately 900°

C. for approximately 10 seconds to 3 hours.

29. The method of claim 28, wherein the heat-treating of the electrode is performed under a gaseous atmosphere containing at least one of nitrogen, argon, helium, oxygen, hydrogen, and air, or under a vacuum.