High efficiency light emitting device

• US 20070029541A1
• Filed: 08/04/2005
• Published: 02/08/2007
• Est. Priority Date: 08/04/2005
• Status: Abandoned Application

• Current Assignee: Xepix Corporation
• Original Assignee: Xepix Corporation
• Inventors: Song, Jin, Shi, Xiaohong, Liu, Xingquan, Xin, Huoping, Choi, Chan
• Application Number:
  US11/196,856
• Publication Number:
  US 20070029541A1
• Time in Patent Office: Days
• US Class Current: 257/14
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• 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 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

A highly efficient III-nitride/II-Oxide light emitting device that has a n⁺⁺-tunneling layer, which comprises at least one material selected from a group consisting of n⁺⁺-GaN, n⁺⁺-InGaN, n⁺⁺-AlGaN, n⁺⁺-AlGaInN, n⁺⁺-ZnO, n⁺⁺-ZnCdO, n⁺⁺-ZnMgO, n⁺⁺-ZnMgCdO, that is deposited on top of the p-layer in a LED structure. After that, a top n-layer is deposited above that n⁺⁺-tunneling layer that may be a n⁺-layer and comprises at least one material selected from a group consisting of n⁺-GaN, n⁺-InGaN, n⁺-AlGaN, n⁺-AlGaInN, n⁺-ZnO, n⁺-ZnCdO, n⁺-ZnMgO, n⁺-ZnMgCdO or a top n-layer may also be a n⁺⁺-layer and comprises at least one material selected from a group consisting of n⁺⁺-GaN, n⁺⁺-InGaN, n⁺⁺-AlGaN, n⁺⁺-AlGaInN, n⁺⁺-ZnO, n⁺⁺-ZnCdO, n⁺⁺-ZnMgO, n⁺⁺-ZnMgCdO so that the top n-layer is made highly conductive and show very rough surface.

Claims

1. A high efficiency LED structure, comprising:

a substrate;

a low-temperature nucleation layer that is on top of the substrate;

a bottom n-type semiconductor layer on top of the low-temperature nucleation layer;

an active layer on top of the n-type semiconductor layer;

a p-type semiconductor layer on top of the active layer;

an n⁺⁺-tunneling layer on top of the p-type semiconductor layer;

a top n-layer on top of the n⁺⁺-tunneling layer; and

an electrode contact coupled to the top n-layer and another electrode contact coupled to the bottom n-type semiconductor layer.

2. The high efficiency LED structure of claim 1, wherein substrate is made up of at least one material selected from a group consisting of SiC, Si, ZnO, MgO, Zn₁₋

x−

yMg_xCd_yO, (where x=0˜

1, y=0˜

1), ZnSO, LiAlO₂, LiGaO₂, MgAl₂O₄, ScAlMgO₄, Al₂O₃(sapphire), AlN, GaN, InN, Al<sub>1−

x−

y</sub>In_xGa_yN, (where x=0˜

1, y=0˜

1), InP, GaAs, and glass.

3. The high efficiency LED structure of claim 1, wherein the bottom n-type semiconductor layer is an n-type III-nitride layer.

4. The high efficiency LED structure of claim 3, where the n-type III-nitride is selected from a group consisting of n-GaN, n-InGaN, n-AlGaN, and n-AlGaInN.

5. The high efficiency LED structure of claim 3, where the n-type III-nitride is a n-type II-oxide layer.

6. The high efficiency LED structure of claim 1, wherein the active region is made up of at least one material selected from a group consisting of GaN, InGaN, AlGaN, AlGaInN, ZnO, ZnMgO, ZnCdO and ZnMgCdO.

7. The high efficiency LED structure of claim 1, wherein the p-layer is made of at least one material selected from a group consisting of p-GaN, p-InGaN, p-AlGaN, p-AlGaInN, p-ZnO, p-ZnMgO, p-ZnCdO and p-ZnMgCdO.

8. The high efficiency LED structure of claim 1, wherein the ne-tunneling layer is made of at least one material selected from a group consisting of n⁺⁺-GaN, n⁺⁺-InGaN, n⁺-AlGaN, n⁺-AlGaInN, n⁺⁺-ZnO, n⁺⁺-ZnCdO, n⁺⁺-ZnMgO, n⁺⁺-ZnMgCdO.

9. The high efficiency LED structure of claim 1, wherein the n⁺⁺-tunneling layer is made of an n⁺⁺-SPS layer made up of any two nitride or oxide compounds such that the n⁺⁺-tunneling layer is super conductive with electron concentration in the range of 1e19 to 5e20 cm⁻

3.

10. The high efficiency LED structure of claim 9, where the n⁺⁺-tunneling layer has a thickness in the range of 0.5 to 100 nm.

11. The high efficiency LED structure of claim 1, wherein the top n-layer made up of at least one material selected from a group consisting of n⁺-GaN, n⁺-InGaN, n⁺-AlGaN, n⁺-AlGaInN, n⁺-ZnO, n⁺-ZnCdO, n⁺-ZnMgO, and n⁺-ZnMgCdO.

12. The high efficiency LED structure of claim 11, where the top n-layer has an electron concentration in the range of 2e18 to 1e20 cm⁻

3 electrons.

13. The high efficiency LED structure of claim 11, where the top n-layer thickness is in the range of 5 to 2000 nm.

14. The high efficiency LED structure of claim 1, wherein the top n-layer is made from at least one material selected from a group consisting of n⁺⁺-GaN, n⁺⁺-InGaN, n⁺⁺-AlGaN, n⁺⁺-AlGaInN, n⁺⁺-ZnO, n⁺⁺-ZnCdO, n⁺⁺-ZnMgO, and n⁺⁺-ZnMgCdO.

15. The high efficiency LED structure of claim 14, where the top n-layer has an electron concentration in the range of 1e19 to 5e20 cm⁻

3.

16. The high efficiency LED structure of claim 14, where the top n-layer thickness is in the range of 5 to 2000 nm.

17. The high efficiency LED structure of claim 1, wherein said top n-layer has a roughness of 0.01˜

1 nm, and is exposed to the ambient with 1˜

100% of its surface.

18. The high efficiency LED structure of claim 1, wherein all layers are grown by at least one growth approach selected from the group growth approaches consisting of Metal-Organic Vapor Phase Epitaxy (MOCVD), Hydride Vapor Phase Epitaxy (HVPE), Molecular beam Epitaxy (MBE), sputtering, pulsed laser deposition, chemical vapor deposition, and physical vapor deposition.

19. The high efficiency LED structure of claim 1, wherein the electrode contact and the other electrode contact are made from metals that are selected from a group of materials consisting of Au, Pt, Al, Ti, Co, Pd, Cu, Ta, and Ni.

20. A method for a high efficiency LED structure, comprising:

forming a low-temperature nucleation layer on top of a substrate;

forming a bottom n-type semiconductor layer on top of the low-temperature nucleation layer;

forming an active layer on top of the n-type semiconductor layer;

forming a p-type semiconductor layer on top of the active layer;

forming an n⁺⁺-tunneling layer on top of the p-type semiconductor layer;

forming a top n-layer on top of the n⁺⁺-tunneling layer; and

creating an electrode contact coupled to the top n-layer and another electrode contact coupled to the bottom n-type semiconductor layer.

21. The method for a high efficiency LED structure of claim 20, wherein substrate is made up of at least one material selected from a group consisting of SiC, Si, ZnO, MgO, Zn₁₋

x−

yMg_xCd_yO (where x=0˜

1, y=0˜

1), ZnSO, LiAlO₂, LiGaO₂, MgAl₂O₄, ScAlMgO₄, A1₂O₃(sapphire), AlN, GaN, InN, Al<sub>1−

x−

y</sub>In_xGa_yN, (where x=0˜

1, y=0˜

1), InP, GaAs, and glass.

22. The method for a high efficiency LED structure of claim 20, wherein the bottom n-type semiconductor layer is an n-type III-nitride layer.

23. The method for a high efficiency LED structure of claim 22, where the n-type III-nitride is selected from a group consisting of n-GaN, n-InGaN, n-AlGaN, and n-AlGaInN.

24. The method for a high efficiency LED structure of claim 22, where the n-type III-nitride is a n-type II-oxide layer.

25. The method for a high efficiency LED structure of claim 20, wherein the active region is made up of at least one material selected from a group consisting of GaN, InGaN, AlGaN, AlGaInN, ZnO, ZnMgO, ZnCdO and ZnMgCdO.

26. The method for a high efficiency LED structure of claim 20, wherein the p-layer is made of at least one material selected from a group consisting of p-GaN, p-InGaN, p-AlGaN, p-AlGaInN, p-ZnO, p-ZnMgO, p-ZnCdO and p-ZnMgCdO.

27. The method for a high efficiency LED structure of claim 20, wherein the n⁺⁺-tunneling layer is made of at least one material selected from a group consisting of n⁺⁺-GaN, n⁺⁺-InGaN, n⁺⁺-AlGaN, n⁺⁺-AlGaInN,.n⁺⁺-ZnO, n⁺⁺-ZnCdO, n⁺⁺-ZnMgO, n⁺⁺-ZnMgCdO.

28. The method for a high efficiency LED structure of claim 20, wherein the n⁺⁺-tunneling layer is made of an n⁺⁺-SPS layer made up of any two nitride or oxide compounds such that the n⁺⁺-tunneling layer is super conductive with electron concentration in the range of 1e19 to 5e20 cm³.

29. The method for a high efficiency LED structure of claim 28, where the n⁺⁺-tunneling layer has a thickness in the range of 0.5 to 100 nm.

30. The method for a high efficiency LED structure of claim 20, wherein the top n-layer made up of at least one material selected from a group consisting of n⁺-GaN, n⁺-InGaN, n⁺-AlGaN, n⁺-AlGaInN, n⁺-ZnO, n⁺-ZnCdO, n⁺-ZnMgO, and n⁺-ZnMgCdO.

31. The method for a high efficiency LED structure of claim 30, where the top n-layer has an electron concentration in the range of 2e18 to 1e20 cm⁻

3 electrons.

32. The method for a high efficiency LED structure of claim 30, where the top n-layer thickness is in the range of 5 to 2000 nm.

33. The high efficiency LED structure of claim 20, wherein the top n-layer is made from at least one material selected from a group consisting of n⁺⁺-GaN, n⁺⁺-InGaN, n⁺⁺-AlGaN, n⁺⁺-AlGaInN, n⁺⁺-ZnO, n⁺⁺-ZnCdO, n⁺⁺-ZnMgO, and n⁺⁺-ZnMgCdO.

34. The high efficiency LED structure of claim 33, where the top n-layer has an electron concentration in the range of 1e19 to 5e20 cm⁻

3.

35. The high efficiency LED structure of claim 33, where the top n-layer thickness is in the range of 5 to 2000 nm.

36. The high efficiency LED structure of claim 20, wherein said top n-layer has a roughness of 1˜

1,000 nm, and is exposed to the ambient with 1˜

100% of its surface.

37. The high efficiency LED structure of claim 20, wherein all layers are grown by at least one procedure selected from the group consisting of Metal-Organic Vapor Phase Epitaxy (MOCVD), Hydride Vapor Phase Epitaxy (HVPE), Molecular beam Epitaxy (MBE), sputtering, pulsed laser deposition, chemical vapor deposition, and physical vapor deposition.

38. The high efficiency LED structure of claim 20, wherein the electrode contact and the other electrode contact are made from metals that are selected from a group of materials consisting of Au, Pt, Al, Ti, Co, Pd, Cu, Ta, and Ni.