Light emitting diode and method of fabricating the same
View Patent ↗Exemplary embodiments of the present invention disclose a light emitting diode including an n-type contact layer doped with silicon, a p-type contact layer, an active region disposed between the n-type contact layer and the p-type contact layer, a superlattice layer disposed between the n-type contact layer and the active region, the superlattice layer including a plurality of layers, an undoped intermediate layer disposed between the superlattice layer and the n-type contact layer, and an electron reinforcing layer disposed between the undoped intermediate layer and the superlattice layer. Only a final layer of the superlattice layer closest to the active region is doped with silicon, and the silicon doping concentration of the final layer is higher than that of the n-type contact layer.
1. A light emitting diode, comprising:
an n-type contact layer;
a p-type contact layer disposed on the n-type contact layer;
an active region comprising a multi-quantum well structure, the active region disposed between the n-type contact layer and the p-type contact layer; and
a spacer layer disposed between the n-type contact layer and the active region,
wherein the spacer layer is doped with n-type impurities, and the n-type impurity doping concentration is relatively higher than the impurity doping concentration of the n-type contact layer, and the active region is undoped, and
wherein the spacer layer comprises In, the content of In being lower than that of indium (In) in a barrier layer of the active region and higher than that of In in a well layer of the active region.
2. The light emitting diode of claim 1 , wherein the active region comprises a multi-quantum well structure comprising an InGaN layer.
3. The light emitting diode of claim 1 , wherein the spacer layer comprises an InGaN layer.
4. The light emitting diode of claim 3 , wherein the spacer layer comprises an alternately stacked In x Ga 1-x N (0≦x<1) layer and In y Ga 1-y N (0≦y<1) layer.
5. The light emitting diode of claim 1 , wherein the spacer layer comprises alternately stacked superlattice layers.
6. The light emitting diode of claim 1 , wherein the spacer layer comprises a plurality of layers, at least one layer of the plurality of layers adjacent to the active region being doped with n-type impurities, the remaining layers of the plurality of layers being undoped with the n-type impurities, and the n-type impurity doping concentration being relatively higher than the impurity doping concentration of the n-type contact layer.
7. The light emitting diode of claim 1 , further comprising an intermediate layer disposed between the spacer layer and the n-type contact layer, wherein the intermediate layer comprises a layer doped with the n-type impurities at a concentration relatively higher than the impurity doping concentration of the n-type contact layer and relatively lower than the n-type impurity doping concentration of the spacer layer.
8. The light emitting diode of claim 7 , wherein the intermediate layer comprises an n-type AlGaN layer.
9. The light emitting diode of claim 8 , wherein the n-type AlGaN layer comprises a gradually or stepwise reduced Al composition toward the active region.
10. The light emitting diode of claim 8 , wherein the n-type AlGaN layer comprises a multi-layer film structure comprising AlGaN/GaN layers or AlGaN/InGaN layers.
11. The light emitting diode of claim 8 , wherein the intermediate layer further comprises an n-GaN layer disposed between the spacer layer and the n-type AlGaN layer.
12. The light emitting diode of claim 8 , wherein the intermediate layer comprises at least one of an undoped GaN layer and a low-doped n-GaN layer disposed between the n-type AlGaN layer and the n-type contact layer.
13. The light emitting diode of claim 1 , further comprising a p-type clad layer disposed between the active region and the p-type contact layer.
14. The light emitting diode of claim 13 , wherein the p-type clad layer comprises a p-type AlGaN layer.
15. The light emitting diode of claim 14 , wherein the p-type AlGaN layer comprises a multi-layer film structure comprising AlGaN/GaN layers or AlGaN/InGaN layers.
16. The light emitting diode of claim 15 , wherein a layer of the multi-layer film structure of the p-type AlGaN layer adjacent to the active region comprises AlGaN.
17. The light emitting diode of claim 15 , wherein the AlGaN layer of the p-type AlGaN layer adjacent to the active region is thinner than other layers within the p-type clad layer.
18. The light emitting diode of claim 14 , wherein the p-type AlGaN comprises a gradually or stepwise reduced Al composition toward the p-type contact layer.
19. The light emitting diode of claim 13 , further comprising an InAlN layer disposed between the active region and the p-type clad layer.
20. The light emitting diode of claim 19 , wherein the InAlN layer comprises a superlattice structure comprising InN/AlN.
21. The light emitting diode of claim 20 , wherein the InAlN layer comprises an InN layer doped with p-type impurities in the superlattice structure.
22. A light emitting diode, comprising:
an n-type contact layer;
a p-type contact layer disposed on the n-type contact layer;
an active region comprising a multi-quantum well structure, the active region disposed between the n-type contact layer and the p-type contact layer; and
a spacer layer disposed between the n-type contact layer and the active region,
wherein the spacer layer is doped with n-type impurities, and the n-type impurity doping concentration is relatively higher than the impurity doping concentration of the n-type contact layer, and the active region is undoped, and
wherein the spacer layer comprises a plurality of layers, at least one layer of the plurality of layers adjacent to the active region being doped with n-type impurities, the remaining layers of the plurality of layers being undoped with the n-type impurities, and the n-type impurity doping concentration being relatively higher than the impurity doping concentration of the n-type contact layer.
23. The light emitting diode of claim 22 , wherein the spacer layer comprises In, the content of In being lower than that of indium (In) in a barrier layer of the active region and higher than that of In in a well layer of the active region.
24. The light emitting diode of claim 22 , wherein the active region comprises a multi-quantum well structure comprising an InGaN layer.
25. The light emitting diode of claim 22 , wherein the spacer layer comprises an InGaN layer.
26. The light emitting diode of claim 25 , wherein the spacer layer comprises an alternately stacked In x Ga 1-x N (0≦x<1) layer and In y Ga 1-y N (0≦y<1) layer.
27. The light emitting diode of claim 22 , wherein the spacer layer comprises alternately stacked superlattice layers.
28. The light emitting diode of claim 22 , further comprising an intermediate layer disposed between the spacer layer and the n-type contact layer, wherein the intermediate layer comprises a layer doped with the n-type impurities at a concentration relatively higher than the impurity doping concentration of the n-type contact layer and relatively lower than the n-type impurity doping concentration of the spacer layer.
29. The light emitting diode of claim 28 , wherein the intermediate layer comprises an n-type AlGaN layer.
30. The light emitting diode of claim 29 , wherein the n-type AlGaN layer comprises a gradually or stepwise reduced Al composition toward the active region.
31. The light emitting diode of claim 29 , wherein the n-type AlGaN layer comprises a multi-layer film structure comprising AlGaN/GaN layers or AlGaN/InGaN layers.
32. The light emitting diode of claim 29 , wherein the intermediate layer further comprises an n-GaN layer disposed between the spacer layer and the n-type AlGaN layer.
33. The light emitting diode of claim 29 , wherein the intermediate layer comprises at least one of an undoped GaN layer and a low-doped n-GaN layer disposed between the n-type AlGaN layer and the n-type contact layer.
34. The light emitting diode of claim 22 , further comprising a p-type clad layer disposed between the active region and the p-type contact layer.
35. The light emitting diode of claim 34 , wherein the p-type clad layer comprises a p-type AlGaN layer.
36. The light emitting diode of claim 35 , wherein the p-type AlGaN layer comprises a multi-layer film structure comprising AlGaN/GaN layers or AlGaN/InGaN layers.
37. The light emitting diode of claim 36 , wherein a layer of the multi-layer film structure of the p-type AlGaN layer adjacent to the active region comprises AlGaN.
38. The light emitting diode of claim 36 , wherein the AlGaN layer of the p-type AlGaN layer adjacent to the active region is thinner than other layers within the p-type clad layer.
39. The light emitting diode of claim 35 , wherein the p-type AlGaN comprises a gradually or stepwise reduced Al composition toward the p-type contact layer.
40. The light emitting diode of claim 34 , further comprising an InAlN layer disposed between the active region and the p-type clad layer.
41. The light emitting diode of claim 40 , wherein the InAlN layer comprises a superlattice structure comprising InN/AlN.
42. The light emitting diode of claim 41 , wherein the InAlN layer comprises an InN layer doped with p-type impurities in the superlattice structure.