Diode having vertical structure and method of manufacturing the same

• US 7,915,632 B2
• Filed: 07/21/2010
• Issued: 03/29/2011
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yoo, Myung Cheol
• Primary Examiner(s): TRAN, MINH LOAN
• Application Number:
  US12/840,840
• Publication Number:
  US 20100314607A1
• Time in Patent Office: 251 Days
• Field of Search: 257/98, 257/99, 257/100, 257/E33.068
• US Class Current: 257/98
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/325 characterised by the doping materials
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01S 5/3013 AIIIBV compounds

Abstract

A light emitting diode includes a conductive layer, an n-GaN layer on the conductive layer, an active layer on the n-GaN layer, a p-GaN layer on the active layer, and a p-electrode on the p-GaN layer. The conductive layer is an n-electrode.

Claims

1. A light emitting device comprising:

a metal layer;

a reflective conductive layer on the metal layer, the reflective conductive layer serving as a first electrode;

a first-type GaN-based layer having a first surface on the reflective conductive layer;

an active layer on the first-type GaN-based layer; and

a second-type GaN-based layer on the active layer;

a second electrode on a second surface of the second-type GaN-based layer, wherein the second surface is opposite the first surface with respect to the active layer,

wherein the reflective conductive layer and the second surface are configured such that the reflective conductive layer reflects light from the active layer back through the second surface.

2. The light emitting device according to claim 1, wherein the reflective conductive layer comprises at least one of Al, Ti/Al, Cr/Au and Ti/Au.

3. The light emitting device according to claim 1, wherein the reflective conductive layer comprises at least one of Al, Ti, Cr and Au.

4. The light emitting device according to claim 1, wherein the second electrode comprises at least one of Ni/Au, Pd/Au, Pd/Ni and Pt.

5. The light emitting device according to claim 1, wherein the second electrode comprises at least one of Ni, Au, Pd and Pt.

6. The light emitting device according to claim 1, wherein the active layer comprises AlInGaN.

7. The light emitting device according to claim 1, wherein the active layer comprises at least one of a quantum well layer and a double hetero structure.

8. The light emitting device according to claim 1, further comprising a cladding layer on the active layer.

9. The light emitting device according to claim 8, wherein the cladding layer is arranged between the second-type GaN-based layer and the active layer.

10. The light emitting device according to claim 8, wherein the cladding layer comprises AlGaN.

11. The light emitting device according to claim 1, wherein the metal layer is located at the bottom of the device.

12. The light emitting device according to claim 1, wherein the metal layer contacts the reflective conductive layer.

13. The light emitting device according to claim 1, wherein the metal layer is configured to serve as a first pad.

14. The light emitting device according to claim 1, wherein the metal layer comprises Au.

15. The light emitting device according to claim 1, further comprising a transparent layer on the second-type GaN-based layer.

16. The light emitting device according to claim 15, wherein the transparent layer comprises a transparent contact.

17. The light emitting device according to claim 16, the transparent contact comprises a transparent conductive oxide.

18. The light emitting device according to claim 16, wherein the transparent contact comprises indium-tin-oxide.

19. The light emitting device according to claim 1, further comprising a buffer layer between the first-type GaN-based layer and the reflective conductive layer.

20. The light emitting device according to claim 19, wherein a thickness of the buffer layer is about 1-2 μ

m.

21. The light emitting device according to claim 1, further comprising a second pad on the second electrode.

22. The light emitting device according to claim 21, wherein the second pad comprises Au.

23. The light emitting device according to claim 21, wherein a width of the second pad is substantially the same as a width of the second electrode.

24. The light emitting device according to claim 21, wherein the second pad overlaps the second electrode.

25. The light emitting device according to claim 21, wherein a thickness of the second pad is about 0.5 μ

m or higher.

26. The light emitting device according to claim 1, wherein the active layer has about 22% of indium composition.

27. The light emitting device according to claim 1, wherein the active layer has about 40% of indium composition.

28. The light emitting device according to claim 1, wherein the active layer has 22% to 40% of indium composition.

29. The light emitting device according to claim 1, wherein the first-type is n-type and the second-type is p-type.

30. The light emitting device according to claim 1, wherein the first-type GaN-based layer is doped with Si.

31. The light emitting device according to claim 30, wherein the doping concentration of Si is about 10¹⁷ cm⁻

3 or greater.

32. The light emitting device according to claim 1, wherein the second-type GaN-based layer is doped with Mg.

33. The light emitting device according to claim 32, wherein the doping concentration of Mg is about 10¹⁷ cm⁻

3 or greater.

34. The light emitting device according to claim 1, wherein the second electrode is located at or near an edge of the second surface.

35. The light emitting device according to claim 1, wherein the reflective conductive layer has a third surface facing the first surface, and wherein the area of the first surface is substantially the same as the area of the third surface.

36. The light emitting device according to claim 1, wherein a width of the reflective conductive layer is substantially the same as a width of the metal layer.

37. The light emitting device according to claim 1, wherein a width of the active layer is substantially the same as a width of the first-type GaN-based layer.

38. The light emitting device according to claim 37, wherein the width of the active layer is configured to enhance brightness of the device.

39. The light emitting device according to claim 1, wherein a width of the active layer is substantially the same as a lateral width of the device.

40. The light emitting device according to claim 1, wherein the reflective conductive layer and the second electrode are substantially vertically arranged with respect to the active layer so as to reduce an effect from static electricity therebetween.

41. The light emitting device according to claim 1, wherein the reflective conductive layer and the second electrode are substantially vertically arranged with respect to the active layer so as to be suitable for a high voltage device.

42. The light emitting device according to claim 1, wherein the reflective conductive layer and the second electrode are substantially vertically arranged with respect to the active layer so as to enhance brightness of the device.