Light emitting device having vertical structure and method for manufacturing the same
View Patent ↗A light emitting device having a vertical structure and a method for manufacturing the same, which are capable of increasing light extraction efficiency, are disclosed. The method includes forming a light extraction layer on a substrate, forming a plurality of semiconductor layers on the light extraction layer, forming a first electrode on the semiconductor layers, forming a support layer on the first electrode, removing the substrate, and forming a second electrode on a surface from which the substrate is removed.
1. A light emitting device having a vertical topology structure, comprising:
a conductive support structure;
a first electrode on the conductive support structure;
a semiconductor structure comprising a p-type semiconductor layer on the first electrode,
a light emitting layer on the p-type semiconductor layer and an n-type semiconductor layer on
the light emitting layer;
a light extraction structure comprising a plurality of holes arranged on the n-type semiconductor layer and a transparent layer contacting a plurality of unfilled holes, wherein the hole plurality of holes have a depth in the range of 0.3 μm to 5 μm;
a second electrode on the semiconductor structure, the second electrode having a first width in a first direction; and
a reflective layer located between the transparent layer and the second electrode, the reflective layer having the first width in the first direction,
wherein the second electrode and the reflective layer overlap with each other across the first width,
wherein a dielectric material is formed in the plurality of holes, the dielectric material located between the transparent layer and the n-type semiconductor layer, and
wherein the transparent layer is disposed on an inner surface of the plurality of unfilled holes with a thickness smaller than a radius of the plurality of holes, and wherein the transparent layer is configured to enhance light emission efficiency of the device.
2. The light emitting device according to claim 1 , wherein a radius of each hole of the plurality of holes is in the range of 0.01 μm to 6 μm.
3. The light emitting device according to claim 1 , wherein the plurality of holes are periodically distributed.
4. The light emitting device according to claim 3 , wherein the light extraction structure has a period in the range of 0.03 μm to 18 μm.
5. The light emitting device according to claim 3 , wherein the first electrode comprises an ohmic electrode and a reflective electrode.
6. The light emitting device according to claim 5 , wherein the reflective electrode has a first surface facing the ohmic electrode and a second surface facing the conductive support structure, and wherein an area of the second surface is larger than an area of the first surface.
7. The light emitting device according to claim 1 , wherein the transparent layer comprises a transparent ohmic layer.
8. The light emitting device according to claim 7 , wherein the transparent ohmic layer comprises at least one of Ti, Al and Au.
9. The light emitting device according to claim 1 , wherein the first electrode comprises material selected from the group consisting of ITO, ZnO, A 1 ZnO, InZnO and a combination thereof.
10. The light emitting device according to claim 1 , wherein the transparent layer extends outside of the plurality of holes.
11. The light emitting device according to claim 10 , wherein the thickness of the transparent layer outside of the plurality of holes is substantially the same as the thickness of the transparent layer disposed on the inner surface of the pluarlity of unfilled holes.
12. The light emitting device according to claim 1 , wherein the first electrode has a first surface facing the p-type semiconductor layer and the p-type semiconductor layer has a second surface facing the first electrode, and wherein an area of the second surface is larger than the area of the first surface.
13. The light emitting device according to claim 1 , wherein the light extraction structure is an integral element of the n-type semiconductor layer.
14. The light emitting device according to claim 1 , wherein the light extraction structure comprises a surface of the n-type semiconductor layer facing the second electrode.
15. The light emitting device according to claim 1 , wherein the conductive support structure comprises metal or semiconductor.
16. The light emitting device according to claim 15 , wherein the metal comprises at least one of Cu, Au and Ni.
17. The light emitting device according to claim 1 , further comprising:
an ohmic-forming layer on the first electrode.
18. The light emitting device according to claim 17 , wherein the ohmic-forming layer comprises an n-type GaN layer.
19. The light emitting device according to claim 17 , wherein the ohmic-forming layer is configured to improve the ohmic characteristics between the first electrode and the semiconductor structure.
20. The light emitting device according to claim 1 , further comprising: a metal layer between the conductive support structure and the first electrode.
21. The light emitting device according to claim 20 , wherein the metal layer contacts the conductive support structure.
22. The light emitting device according to claim 20 , wherein the metal layer contacts the first electrode.
23. The light emitting device according to claim 1 , wherein the transparent layer contacts the second electrode.
24. The light emitting device according to claim 1 , wherein the depth of the plurality of holes is substantially the same as the thickness of the n-type semiconductor layer.
25. The light emitting device according to claim 1 , wherein the thickness of the light extraction structure is substantially the same as the thickness of the n-type semiconductor layer.
26. The light emitting device according to claim 1 , wherein the transparent layer has a substantially uniform thickness at least inside of the plurality of unfilled holes.
27. The light emitting device according to claim 1 , wherein the light extraction structure comprises the same material as that of the n-type semiconductor layer.
28. The light emitting device according to claim 1 , wherein the conductive support structure contacts the first electrode.
29. The light emitting device according to claim 1 , wherein the transparent layer covers an entire upper surface of the n-type semiconductor layer.
30. The light emitting device according to claim 1 , wherein the transparent layer is conductive.
31. The light emitting device according to claim 1 , wherein the first electrode has a first surface facing the conductive support structure and the conductive support structure has a second surface facing the first electrode, and wherein an area of the first surface is substantially the same as an area of the second surface.
32. The light emitting device according to claim 1 , wherein the first electrode has a first surface facing the semiconductor structure, and wherein a side surface of the semiconductor structure is substantially vertical to the first surface of the first electrode.