Light emitting diode and method of fabricating the same

• US 10,418,514 B2
• Filed: 07/06/2017
• Issued: 09/17/2019
• Est. Priority Date: 01/05/2010
• 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, Kwang Joong, Han, Chang Suk, Ye, Kyung Hee, Choi, Seung Kyu, Nam, Ki Bum, Kim, Nam Yoon, Kim, Kyung Hae, Yoon, Ju Hyung
• Primary Examiner(s): Smith, Bradley
• Assistant Examiner(s): Goodwin, David J
• Application Number:
  US15/643,403
• Publication Number:
  US 20170309775A1
• Time in Patent Office: 803 Days
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 33/0025 comprising only AIIIBV compounds
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

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.

Claims

1. A light emitting diode, comprising:

an n-type contact layer;

a p-type contact layer disposed over the n-type contact layer;

an active region disposed between the n-type contact layer and the p-type contact layer and comprising a multi-quantum well structure including a quantum well layer;

a p-type clad layer disposed between the p-type contact layer and the active region;

a superlattice layer including a plurality of layers, disposed near the active region; and

a spacer layer disposed between the superlattice layer and the n-type contact layer and having a bandgap smaller than that of the barrier layer and greater than that of the quantum well layer.

2. The light emitting diode of claim 1, further comprising an un-doped intermediate layer disposed between the n-type contact layer and the active region.

3. The light emitting diode of claim 1, wherein the spacer layer comprises a stacked structure of at least two different InGaN layers.

4. The light emitting diode of claim 1, wherein the at least one layer of the plurality of layers in the spacer layer positioned adjacent to the active region is doped with n-type impurities.

5. The light emitting diode of claim 1, wherein:

the n-type contact layer includes n-type impurities; and

the at least one of the plurality of layers in the spacer layer that is doped with n-type impurities is doped with the n-type impurities at a higher concentration than a concentration of the n-type impurities in the n-type contact layer.

6. The light emitting diode of claim 1, further comprising:

an intermediate layer disposed between the n-type contact layer and the spacer layer and including n-type impurities, wherein a concentration of the n-type impurities in the intermediate layer is higher than a concentration of n-type impurities in the n-type contact layer and lower than a concentration of n-type impurities in the spacer layer.

7. The light emitting diode of claim 6, wherein the intermediate layer includes an n-AlGaN layer.

8. The light emitting diode of claim 7, wherein the n-AlGaN layer in the intermediate layer has a gradually or stepwise reduced Al composition toward the active region than away from the active region.

9. The light emitting diode of claim 1, wherein the p-type clad layer includes an AlGaN layer.

10. The light emitting diode of claim 9, wherein Al composition of the AlGaN layer is gradually lowered toward the p-type contact layer.

11. The light emitting diode of claim 9, further comprising an intermediate layer disposed between the n-type contact layer and the active region, wherein Al composition of the AlGaN layer is greater than that of the intermediate layer.

12. The light emitting diode of claim 1, wherein the p-type clad layer includes a plurality of layers including at least one of AlGaN, GaN, or InGaN.

13. The light emitting diode of claim 1, wherein the p-type clad layer includes a first layer and a second layer, the first layer is closer to the active region than the second layer is, and the first layer has a thickness smaller than the second layer.

14. A light emitting diode, comprising:

an n-type contact layer doped with n-type impurities;

a spacer layer disposed over the n-type contact layer and having a bandgap smaller than that of the barrier layer and greater than that of the quantum well layer;

an active region disposed over the spacer layer and having a multi-quantum well structure including a quantum well layer and a barrier layer;

a p-type contact layer disposed over the active region; and

a p-type clad layer disposed between the p-type contact layer and the active region.

15. The light emitting diode of claim 14, wherein the quantum well layer includes an InGaN layer.

16. The light emitting diode of claim 14, wherein the active region is not doped with the n-type impurities.

17. The light emitting diode of claim 14, wherein the spacer layer includes a first semiconductor layer not doped with the n-type impurities and a second semiconductor layer doped with the n-type impurities.

18. The light emitting diode of claim 14, wherein the spacer layer is doped with n-type impurities at higher concentration than a concentration of the n-type impurities in the n-type contact layer.

19. The light emitting diode of claim 14, further comprising an intermediate layer formed between the n-type contact layer and the spacer layer and including n-AlGaN layer.

20. The light emitting diode of claim 19, wherein the intermediate layer is doped with the n-type impurities at a concentration that is higher than a concentration of the n-type impurities in the n-type contact layer.

21. The light emitting diode of claim 19, wherein the n-AlGaN layer has a gradually or stepwise reduced Al composition toward the active region than away from the active region.

22. The light emitting diode of claim 14, wherein the n-type contact layer comprises at least two different n-type GaN layers and an n-type AlGaN layer disposed between the at least two different n-type GaN layers.

23. The light emitting diode of claim 14, wherein the first and second semiconductor layers of the spacer layer include different InGaN layers.

24. The light emitting diode of claim 14, wherein the p-type clad layer includes an AlGaN layer.

25. The light emitting diode of claim 24, wherein Al composition of the AlGaN layer is gradually lowered toward the p-type contact layer.

26. The light emitting diode of claim 24, further comprising an intermediate layer disposed between the n-type contact layer and the active region, wherein Al composition of the AlGaN layer is greater than that of the intermediate layer.

27. The light emitting diode of claim 14, wherein the p-type clad layer includes a plurality of layers including at least one of AlGaN, GaN, or InGaN.

28. The light emitting diode of claim 14, wherein the p-type clad layer includes a first layer and a second layer, the first layer is closer to the active region than the second layer is, and the first layer has a thickness smaller than the second layer.