Light emitting diode, package structure and manufacturing method thereof

• US 8,138,518 B2
• Filed: 04/07/2009
• Issued: 03/20/2012
• Est. Priority Date: 09/22/2008
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Tsai, Yao-Jun, Sheu, Jinn-Kong, Hu, Hung-Lieh, Yen, Hsi-Hsuan
• Primary Examiner(s): Fahmy, Wael
• Assistant Examiner(s): Jahan, Bilkis
• Application Number:
  US12/419,299
• Publication Number:
  US 20100072487A1
• Time in Patent Office: 1,078 Days
• Field of Search: 257/86, 257/94, 257/98, 257/99, 257/100, 257/91, 257/778, 257/87
• US Class Current: 257/99
• 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 layer, 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 layer 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 layer 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 layer, comprising a plurality of patterns disposed on the second semiconductor layer, wherein pitches of the patterns gradually decrease or increase from a position near the first electrode to a position away from the first electrode;

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 layer and electrically connected to the second semiconductor layer.

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

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

4. 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 layer, 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.

5. 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 layer.

6. The light emitting diode of claim 5, further comprising an ohmic contact layer disposed between the metallic reflective layer and the second semiconductor layer and covering the current distribution modifying layer.

7. The light emitting diode of claim 5, wherein the patterns comprises a plurality of protrusions disposed on the second semiconductor layer, and a material of the protrusions is an insulating material.

8. The light emitting diode of claim 7, wherein a material of the protrusions is selected from a group consisting of SiO₂, SiN_x, AlN, SiOxNy and Ga₂O₃.

9. The light emitting electrode of claim 5, wherein a material of the patterns is an ohmic contact material.

10. The light emitting electrode of claim 5, wherein the patterns comprises a plurality of recesses disposed on the second semiconductor layer.

11. The light emitting diode of claim 1, wherein the patterns comprises a plurality of protrusions disposed on the second semiconductor layer, and a material of the protrusions is a conductive material.

12. The light emitting diode of claim 11, wherein the material of the patterns 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).

13. 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.

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

15. 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.

16. The light emitting diode of claim 1, wherein the patterns comprise first sub patterns disposed along an edge of the second semiconductor layer.

17. The light emitting diode of claim 16, wherein the patterns further comprise second sub patterns disposed under the second electrode.

18. The light emitting diode of claim 17, wherein the second sub patterns comprise a plurality of slit patterns.

19. The light emitting diode of claim 1, wherein the patterns comprises a plurality of block patterns or a mesh.