LIGHT EMITTING DIODE, PACKAGE STRUCTURE AND MANUFACTURING METHOD THEREOF

• US 20100072487A1
• Filed: 04/07/2009
• Published: 03/25/2010
• Est. Priority Date: 09/22/2008
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Hu, Hung-Lieh, Tsai, Yao-Jun, Yen, Hsi-Hsuan, Sheu, Jinn-Kong
• Granted Patent: US 8,138,518 B2
• Time in Patent Office: Days
• US Class Current: 257/86
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body

Abstract

A light emitting diode (LED), a fabricating method thereof, and a package structure thereof are provided. The LED includes a substrate, a first semiconductor layer disposed on the substrate, an active layer disposed on the first semiconductor layer, a second semiconductor layer disposed on the active layer, a current distribution modifying pattern, a first electrode and a second electrode. The active layer and the second semiconductor layer form a mesa structure and expose a part of the first semiconductor layer. The current distribution modifying pattern is disposed on the second semiconductor layer. The first electrode is disposed on and electrically connected to the first semiconductor layer exposed by the mesa structure. The second electrode is disposed on the current distribution modifying pattern and is electrically connected to the second semiconductor layer. The LED has superior light emitting efficiency.

Claims

1. A light emitting diode, comprising:

a substrate;

a first semiconductor layer, disposed on the substrate;

an active layer, disposed on the first semiconductor layer;

a second semiconductor layer, disposed on the active layer, wherein the active layer and the second semiconductor layer form a mesa structure, and the mesa structure exposes a part of the first semiconductor layer;

a current distribution modifying pattern, disposed on the second semiconductor layer;

a first electrode, disposed on the first semiconductor layer exposed by the mesa structure and electrically connected to the first semiconductor layer; and

a second electrode, disposed on the current distribution modifying pattern and electrically connected to the second semiconductor layer.

2. The light emitting diode of claim 1, wherein the current distribution modifying pattern is insulating.

3. The light emitting diode of claim 2, wherein the a distribution density of the current distribution modifying pattern on the second semiconductor layer gradually increases from a position near the first electrode to a position away from the first electrode.

4. The light emitting diode of claim 2, wherein the a distribution density of the current distribution modifying pattern on the second semiconductor layer gradually decreases from a position near the first electrode to a position away from the first electrode.

5. The light emitting diode of claim 1, wherein the current distribution modifying pattern is conductive.

6. The light emitting diode of claim 5, wherein the a distribution density of the current distribution modifying pattern on the second semiconductor layer gradually increases from a position near the first electrode to a position away from the first electrode.

7. The light emitting diode of claim 5, wherein the a distribution density of the current distribution modifying pattern on the second semiconductor layer gradually decreases from a position near the first electrode to a position away from the first electrode.

8. The light emitting diode of claim 1, wherein V_A is a voltage drop of a current from the second electrode, transmitted through the current distribution modifying pattern, to the first electrode, V_B is a voltage drop of a current from the second electrode, transmitted downward and through the first semiconductor layer, to the first electrode, and V_A is equal to V_B.

9. The light emitting diode of claim 1, further comprising a metallic reflective layer disposed between the second electrode and the second semiconductor layer and covering the current distribution modifying pattern.

10. The light emitting diode of claim 9, further comprising an ohmic contact layer disposed between the metallic reflective layer and the second semiconductor layer and covering the current distribution modifying pattern.

11. The light emitting diode of claim 9, wherein the current distribution modifying pattern comprises a plurality of protrusions disposed on the second semiconductor layer, and a material of the protrusions is an insulating material.

12. The light emitting diode of claim 11, wherein a material of the protrusions is selected from a group consisting of SiO₂, SiN_x, AlN, SiO_xN_y and Ga₂O₃.

13. The light emitting diode of claim 11, wherein a distribution density of the current distribution modifying layer on the second semiconductor layer decreases from a position near the first electrode to a position away from the first electrode.

14. The light emitting electrode of claim 9, wherein a material of the current distribution modifying pattern is an ohmic contact material.

15. The light emitting electrode of claim 9, wherein the current distribution modifying pattern comprises a plurality of recesses disposed in the second semiconductor layer.

16. The light emitting diode of claim 1, wherein the current distribution modifying pattern comprises a plurality of protrusions disposed on the second semiconductor layer, and a material of the protrusions is a conductive material.

17. The light emitting diode of claim 16, wherein the material of the current distribution modifying pattern is selected from a group consisting of indium tin oxide (ITO), fluorine doped tin oxide (FTO), aluminum doped zinc oxide (AZO), and gallium doped zinc oxide (GZO).

18. The light emitting diode of claim 16, wherein a distribution density of the current distribution modifying pattern on the second semiconductor layer increases from a position near the first electrode to a position away from the first electrode.

19. The light emitting diode of claim 1, wherein the first electrode has a finger structure and comprises a plurality of first branches, and the mesa structure has a finger structure and comprises a plurality of second branches, the first branches and the second branches being parallel to each other and arranged alternately.

20. The light emitting diode of claim 1, wherein the current distribution modifying pattern is formed by patterning a laminated material layer.

21. The light emitting diode of claim 1, further comprising a protection layer covering the first semiconductor layer and the mesa structure and exposing the first electrode and the second electrode.

22. The light emitting diode of claim 1, wherein the current distribution modifying pattern comprises a first sub pattern circling along an edge of the second semiconductor layer.

23. The light emitting diode of claim 22, wherein the current distribution modifying pattern further comprises a second sub pattern disposed under the second electrode.

24. The light emitting diode of claim 23, wherein the second sub pattern comprises a plurality of slit patterns.

25. The light emitting diode of claim 1, wherein the current distribution modifying pattern comprises a plurality of block patterns or a mesh pattern.

26. A package structure of a light emitting diode, comprising:

a light emitting diode unit, comprising;

a first semiconductor layer;

an active layer, disposed on the first semiconductor layer;

a second semiconductor layer, disposed on the active layer, wherein the active layer and the second semiconductor layer form a mesa structure, and the mesa structure exposes a part of the first semiconductor layer;

a current distribution modifying pattern, disposed on the second semiconductor layer;

a first electrode, disposed on the first semiconductor layer exposed by the mesa structure and electrically connected to the first semiconductor layer;

a second electrode, disposed on the current distribution modifying pattern and electrically connected to the second semiconductor layer; and

a package substrate, comprising a first contact and a second contact, wherein the first electrode and the second electrode of the light emitting diode unit face the first contact and the second contact; and

a plurality of electrical connection units, the first contact and the second contact being electrically connected to the first electrode and the second electrode respectively through the electrical connection units.

27. The package structure of the light emitting diode of claim 26, wherein the light emitting diode unit further comprises a metallic reflective layer disposed between the second electrode and the second semiconductor layer and covering the current distribution modifying pattern.

28. The package structure of the light emitting diode of claim 27, wherein the light emitting diode unit further comprises an ohmic contact layer disposed between the metallic reflective layer and the second semiconductor layer and covering the current distribution modifying pattern.

29. The package structure of the light emitting diode of claim 27, wherein the current distribution modifying pattern comprises a plurality of protrusions disposed on the second semiconductor layer, and a material of the protrusions is an insulating material.

30. The package structure of the light emitting diode of claim 29, wherein the material of the protrusions is selected from a group consisting of SiO₂, SiN_x, AlN, SiO_xN_y and Ga₂O₃.

31. The package structure of the light emitting diode of claim 29, wherein a distribution density of the current distribution modifying layer on the second semiconductor layer decreases from a position near the first electrode to a position away from the first electrode.

32. The package structure of the light emitting diode of claim 27, wherein a material of the current distribution modifying pattern is an ohmic contact material.

33. The package structure of the light emitting diode of claim 27, wherein the current distribution modifying pattern comprises a plurality of recesses disposed in the second semiconductor layer.

34. The package structure of the light emitting diode of claim 27, wherein the current distribution modifying pattern comprises a plurality of protrusions disposed on the second semiconductor layer, a material of the protrusions being a conductive material.

35. The package structure of the light emitting diode of claim 34, wherein the material of the current distribution modifying pattern is selected from a group consisting of indium tin oxide (ITO), fluorine doped tin oxide (FTO), aluminum doped zinc oxide (AZO), and gallium doped zinc oxide (GZO).

36. The package structure of the light emitting diode of claim 34, wherein a distribution density of the current distribution modifying layer on the second semiconductor layer increases from a position near the first electrode to a position away from the first electrode.

37. The package structure of the light emitting diode of claim 26, wherein the first electrode has a finger structure and comprises a plurality of first branches, and the mesa structure has a finger structure and comprises a plurality of second branches, the first branches and the second branches being parallel to each other and arranged alternately.

38. The package structure of the light emitting diode of claim 26, wherein the current distribution modifying pattern is formed by patterning a laminated material layer.

39. The package structure of the light emitting diode of claim 26, wherein the light emitting diode unit further comprises a protection layer covering the first semiconductor layer and the mesa structure and exposing the first electrode and the second electrode.

40. The package structure of the light emitting diode of claim 26, wherein the current distribution modifying pattern comprises a first sub pattern circling along an edge of the second semiconductor layer.

41. The package structure of the light emitting diode of claim 40, wherein the current distribution modifying pattern further comprises a second sub pattern disposed below the second electrode.

42. The package structure of the light emitting diode of claim 41, wherein the second sub pattern comprises a plurality of slit patterns.

43. The package structure of the light emitting diode of claim 26, wherein the current distribution modifying pattern comprises a plurality of block patterns or a mesh pattern.

44. The package structure of the light emitting diode of claim 26, wherein the light emitting diode unit further comprises a substrate disposed on a side of the second semiconductor layer away from the package substrate.

45. The package structure of the light emitting diode of claim 26, wherein a surface of the second semiconductor layer away from the package substrate is a rough surface.

46. A fabricating method of a light emitting diode, comprising:

providing a substrate and forming a first semiconductor layer, an active layer and a second semiconductor layer on the substrate, wherein the first semiconductor layer is disposed on the substrate, the active layer is disposed on the first semiconductor layer, and the second semiconductor layer is disposed on the active layer;

patterning the second semiconductor layer and the active layer, so that the second semiconductor layer and the active layer expose a part of the first semiconductor layer;

forming a current distribution modifying pattern on the second semiconductor layer; and

forming a second electrode on the second semiconductor layer, so that the second electrode is electrically connected to the second semiconductor layer, and forming a first electrode on the first semiconductor layer exposed by the active layer and the second semiconductor layer, so that the first electrode is electrically connected to the first semiconductor layer.

47. The fabricating method of the light emitting diode of claim 46, further comprising forming a metallic reflective layer on the second semiconductor layer before forming the second electrode, so that the metallic reflective layer covers the current distribution modifying pattern.

48. The fabricating method of the light emitting diode of claim 47, further comprising forming an ohmic contact layer on the second semiconductor layer before forming the metallic reflective layer, so that the ohmic contact layer covers the current distribution modifying pattern.

49. The fabricating method of the light emitting diode of claim 47, further comprising forming an ohmic contact layer on the second semiconductor layer before forming the metallic reflective layer and patterning the ohmic contact layer to form the current distribution modifying pattern.

50. The fabricating method of the light emitting diode of claim 46, wherein the method of forming the current distribution modifying pattern comprises forming a material layer on the second semiconductor layer and patterning the material layer to form a plurality of protrusions on the second semiconductor layer.

51. The fabricating method of the light emitting diode of claim 46, wherein the method of forming the current distribution modifying pattern comprises etching a surface of the second semiconductor layer to form a plurality of recesses in the second semiconductor layer.

52. The fabricating method of the light emitting diode of claim 46, wherein the method of patterning the second semiconductor layer and the active layer comprises:

forming a mask layer on the second semiconductor layer; and

etching the second semiconductor layer and the active layer through the mask layer.

53. The fabricating method of the light emitting diode of claim 52, wherein the method of forming the current distribution modifying pattern comprises etching the mask layer to form a plurality of protrusions on the second semiconductor layer.

54. The fabricating method of the light emitting diode of claim 46, further comprising forming a protection layer to cover the first semiconductor layer the active layer and the second semiconductor layer and expose the first electrode and the second electrode.