Light emitting diode having improved current spreading efficiency, improved mechanical reliability, or some combination thereof

• US 10,172,190 B2
• Filed: 05/18/2016
• Issued: 01/01/2019
• Est. Priority Date: 06/05/2015
• Status: Active Grant

• Current Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Inventors: Kim, Mae Yi, Lee, Seom Geun, Yoon, Yeo Jin, Lee, Jin Woong, Ryu, Yong Woo
• Primary Examiner(s): Nguyen, Duy T
• Application Number:
  US15/579,370
• Publication Number:
  US 20180153007A1
• Time in Patent Office: 958 Days
• Field of Search: 257 81, 257 99
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• 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 33/36 characterised by the electrodes
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H05B 45/345 Current stabilisation; Maintaining constant current

Abstract

A light emitting diode including a first semiconductor layer and a plurality of mesas including a second semiconductor layer and an active layer interposed between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer including an exposed region between the plurality of mesas, a current blocking layer disposed on a portion of the plurality of mesas and a portion of the exposed region, a transparent electrode layer covering the second semiconductor layer and the current blocking layer, and a second electrode disposed on the current blocking layer and the transparent electrode layer and electrically connected to the second semiconductor layer. The current blocking layer includes a connecting portion extending from a first mesa to a second mesa adjacent to the first mesa and a protruding portion protruding from the connecting portion and disposed on the exposed region.

Claims

1. A light emitting diode, comprising:

a light emitting structure comprising a first conductivity type semiconductor layer and a plurality of mesas comprising a second conductivity type semiconductor layer disposed on the first conductivity type semiconductor layer and an active layer interposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, the first conductivity type semiconductor layer comprising an exposed region between the plurality of mesas;

a first electrode disposed on the first conductivity type semiconductor layer and electrically connected to the first conductivity type semiconductor layer;

a current blocking layer disposed on a portion of the plurality of mesas and a portion of the exposed region;

a transparent electrode layer disposed on a portion of the plurality of mesas and a portion of the exposed region, the transparent electrode layer partially covering the second conductivity type semiconductor layer and the current blocking layer; and

a second electrode disposed on the current blocking layer and the transparent electrode layer and electrically connected to the second conductivity type semiconductor layer,

wherein the current blocking layer comprises a connecting portion extending from a first mesa of the plurality of mesas to a second mesa of the plurality of mesas adjacent to the first mesa, and a protruding portion protruding from the connecting portion and disposed on the exposed region.

2. The light emitting diode according to claim 1, wherein the first conductivity type semiconductor layer comprises:

a first side surface adjacent to the connecting portion;

a second side surface opposite to the first side surface; and

third side surfaces disposed between the first side surface and the second side surface and intersecting each of the first side surface and the second side surface, and

the protruding portion protrudes towards the first side surface or the second side surface.

3. The light emitting diode according to claim 2, wherein:

the plurality of mesas comprises a plurality of second mesas and the first mesa interposed between the plurality of second mesas, the second mesa included in the plurality of second mesas,

the second electrode comprises a second bonding pad disposed on the first mesa and between the connecting portions adjacent to each other,

the first electrode comprises a first bonding pad disposed between the first mesa and the second side surface, and

the light emitting diode has a symmetrical structure with respect to an imaginary line intersecting the first bonding pad and the second bonding pad.

4. The light emitting diode according to claim 3, wherein:

the second electrode comprises an upper extension portion extending from the second bonding pad, and

the upper extension portion comprises a first upper extension portion disposed on the connecting portion and adjoining the second bonding pad, and a second upper extension portion parallel to the third side surfaces.

5. The light emitting diode according to claim 4, wherein a shortest distance between the first upper extension portion and the first side surface is less than a shortest distance between a central portion of the second bonding pad and the first side surface.

6. The light emitting diode according to claim 4, wherein a distance between a distal end of the second upper extension portion and the first side surface is greater than a distance between the distal end of the second upper extension portion and the second side surface.

7. The light emitting diode according to claim 6, wherein the second upper extension portion comprises a second section disposed on the second mesa and parallel to the third side surfaces.

8. The light emitting diode according to claim 7, wherein the second upper extension portion further comprises a first section disposed on the first mesa and between the first bonding pad and the second bonding pad while adjoining the second bonding pad, and the second section has a greater length than the first section.

9. The light emitting diode according to claim 8, wherein the second section has a greater width than the first section.

10. The light emitting diode according to claim 8, wherein a distal end of the second section is directed towards an imaginary line intersecting the first bonding pad and the second bonding pad.

11. The light emitting diode according to claim 7, wherein:

the plurality of mesas further comprise a plurality of third mesas each interposed between the second mesa and the third side surface;

the first mesa is disposed between the plurality of third mesas; and

the second upper extension portion further comprises a third section disposed on each third mesa and parallel to the third side surface.

12. The light emitting diode according to claim 11, wherein the third section has a greater length than the second section.

13. The light emitting diode according to claim 12, wherein the third section has a greater width than the second section.

14. The light emitting diode according to claim 13, wherein:

the protruding portion comprises a first protruding portion,

a distance between a distal end of the first protruding portion and the second side surface is smaller than a distance between the first protruding portion and the first side surface, and

each of the second sections is disposed on the first protruding portion.

15. The light emitting diode according to claim 11, wherein a portion of the second section is disposed on the first mesa and a region of the exposed region disposed between the first mesa and each second mesa.

16. The light emitting diode according to claim 4, wherein the first electrode comprises a lower extension portion connected to the first bonding pad, and a distance between a distal end of the lower extension portion and the second side surface is greater than a distance between the distal end of the lower extension portion and the first side surface.

17. The light emitting diode according to claim 16, wherein the lower extension portion comprises a first lower extension portion disposed on the exposed region.

18. The light emitting diode according to claim 17, wherein the lower extension portion comprises a second lower extension portion disposed between the first bonding pad and the second bonding pad.

19. The light emitting diode according to claim 3, wherein a portion of the second mesa is disposed between the first mesa and the first side surface.

20. The light emitting diode according to claim 1, wherein each mesa of the plurality of mesas is the same size.

21. A light emitting diode comprising:

a light emitting structure comprising a first conductivity type semiconductor layer, and a plurality of mesas comprising a second conductivity type semiconductor layer disposed on the first conductivity type semiconductor layer and an active layer interposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, the first conductivity type semiconductor layer comprising an exposed region between the plurality of mesas;

a first electrode disposed on the first conductivity type semiconductor layer and electrically connected to the first conductivity type semiconductor layer;

a current blocking layer disposed on a portion of the plurality of mesas and a portion of the exposed region;

a transparent electrode layer disposed on a portion of the plurality of mesas and a portion of the exposed region, the transparent electrode layer partially covering the second conductivity type semiconductor layer and the current blocking layer; and

a second electrode disposed on the current blocking layer and the transparent electrode layer and electrically connected to the second conductivity type semiconductor layer,

wherein the current blocking layer comprises a connecting portion extending from a first mesa of the plurality of mesas to a second mesa of the plurality of mesas adjacent to the first mesa;

the plurality of mesas comprises the first mesa and the second mesa disposed adjacent to each other;

the connecting portion comprises a first connecting portion disposed on the first mesa and the second mesa; and

the first connecting portion comprises a first opening exposing an upper surface of the first mesa and a second opening exposing an upper surface of the second mesa, each of the first opening and the second opening comprising at least one concave portion.

22. The light emitting diode according to claim 21, wherein:

the second electrode comprises a second bonding pad disposed on the first connecting portion,

the first electrode comprises a first bonding pad interposed between the first mesa and the second mesa, and

the first opening and the second opening have a symmetrical structure with respect to an imaginary line intersecting the first bonding pad and the second bonding pad.

23. The light emitting diode according to claim 22, wherein the first connecting portion has a circular shape, and each of the concave portions of the first and second openings is parallel to an outer periphery of the first connecting portion.

24. The light emitting diode according to claim 23, wherein each of the first opening and the second opening comprises at least one convex portion,

the convex portion being parallel to the outer periphery of the first connecting portion.

25. The light emitting diode according to claim 24, wherein the second bonding pad contacts the second conductivity type semiconductor layer through the first opening and the second opening.

26. The light emitting diode according to claim 25, wherein the second bonding pad has a circular shape.

27. A light emitting diode, comprising:

a light emitting structure comprising a first conductivity type semiconductor layer, and a plurality of mesas comprising a second conductivity type semiconductor layer disposed on the first conductivity type semiconductor layer and an active layer interposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, the first conductivity type semiconductor layer comprising an exposed region between the plurality of mesas;

a first electrode disposed on the first conductivity type semiconductor layer and electrically connected to the first conductivity type semiconductor layer;

a transparent electrode layer disposed on a portion of the plurality of mesas and a portion of the exposed region;

a current blocking layer interposed between the transparent electrode layer and the second conductivity type semiconductor layer and interposed between the transparent electrode layer and the exposed region; and

a second electrode disposed on the current blocking layer to partially cover the transparent electrode layer and electrically connected to the second conductivity type semiconductor layer,

wherein the transparent electrode layer comprises a plurality of first regions disposed on the plurality of mesas and a second region disposed on the exposed region and adjoining the plurality of first regions.

28. The light emitting diode according to claim 27, wherein portions of the transparent electrode layer disposed on the plurality of mesas are connected to each other.

29. The light emitting diode according to claim 28, wherein the current blocking layer comprises a connecting portion disposed between the second region and the exposed region.

30. The light emitting diode according to claim 29, wherein a portion of the connecting portion on the exposed region has a greater width than a portion of the second region disposed on the exposed region.

31. The light emitting diode according to claim 30, wherein a portion of the second region disposed on the exposed region has a greater width than a portion of the second electrode disposed on the exposed region.

32. The light emitting diode according to claim 27, wherein a side surface of a first region of the plurality of first regions is parallel to a side surface of a mesa of the plurality of mesas.