Optical semiconductor device and method of manufacturing the same

• US 8,227,789 B2
• Filed: 08/28/2009
• Issued: 07/24/2012
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: Dowa Electronics Materials Co. Ltd. (DOWA Holdings Company Limited), Riken
• Original Assignee: Dowa Electronics Materials Co. Ltd. (DOWA Holdings Company Limited), Riken
• Inventors: Hirayama, Hideki, Shibata, Tomohiko
• Primary Examiner(s): Smith, Zandra
• Assistant Examiner(s): PATTON, PAUL E
• Application Number:
  US12/550,329
• Publication Number:
  US 20100219395A1
• Time in Patent Office: 1,061 Days
• Field of Search: 257/13, 257/14, 257/E33.008, 257/E33.027
• US Class Current: 257/13
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• 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 33/32 containing nitrogen

Abstract

Devices and techniques related to UV light-emitting devices that can be implemented in ways that improve the light-emitting efficiency of an UV light-emitting device using a group III nitride semiconductor.

Claims

1. A light-emitting device formed on an AlN-based group III nitride single crystal comprising:

a high-concentration n-type group III nitride layer;

a multi quantum well structure formed of an n-type or i-type group III nitride barrier layer and an n-type or i-type group III nitride well layer;

an i-type group III nitride final barrier layer;

a p-type group III nitride layer; and

an electron blocking layer formed between the i-type group III nitride final barrier layer and the p-type group III nitride layer, the electron blocking layer being formed of a p-type or i-type AlN serving as an energy barrier for electrons from the i-type group III nitride final barrier layer.

3. The light-emitting device according to claim 1, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate.

6. The light-emitting device according to claim 1, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, and wherein a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less.

9. The light-emitting device according to claim 1, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less, and a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm.

12. The light-emitting device according to claim 1, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, and a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm.

14. The light-emitting device according to claim 1, wherein a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

16. The light-emitting device according to claim 1, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, and a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

20. The light-emitting device according to claim 1, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less, and a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

21. The light-emitting device according to claim 1, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm, a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

26. The light-emitting device according to claim 1, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm, a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less, and a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

2. A light-emitting device formed on a group III nitride single crystal comprising:

an AlN-based group III nitride regrowth layer;

a high-concentration n-type AlGaN layer;

a multi quantum well structure formed of an n-type or i-type Al_xGa_1-xN barrier layer and a well layer of an n-type or i-type Al_yGa_1-yN layer (x>

y);

an i-type Al_xGa_1-xN final barrier layer;

a p-type Al_xGa_1-xN layer; and

an electron blocking layer formed between the i-type Al_xGa_1-xN final barrier layer and the p-type Al_xGa_1-xN layer, the electron blocking layer being formed of a p-type or i-type Al_zGa_1-zN layer (z>

x>

y, 0.95<

z≦

1) serving as an energy barrier for electrons from the i-type Al_xGa_1-xN final barrier layer.

4. The light-emitting device according to claim 2, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate.

5. The light-emitting device according to claim 2, wherein a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less.

7. The light-emitting device according to claim 2, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, and wherein a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less.

8. The light-emitting device according to claim 2, wherein a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm.

10. The light-emitting device according to claim 2, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less, and a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm.

11. The light-emitting device according to claim 2, wherein a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less, and a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm.

13. The light-emitting device according to claim 2, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, and a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm.

15. The light-emitting device according to claim 2, wherein a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

17. The light-emitting device according to claim 2, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, and a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

18. The light-emitting device according to claim 2, wherein a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less, and a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

19. The light-emitting device according to claim 2, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, a thickness of the well layer of the Al_yGa1-yN layer is set to 2 nm or less, and a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

22. The light-emitting device according to claim 2, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm, a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

23. The light-emitting device according to claim 2, wherein a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm, and a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

24. The light-emitting device according to claim 2, wherein a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm, a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less, and a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

25. The light-emitting device according to claim 2, wherein the group III nitride single crystal is a group III nitride single crystal film formed on a substrate, a thickness of the i-type Al_xGa_1-xN final barrier layer is set from 2 nm to 10 nm, a thickness of the well layer of the Al_yGa_1-yN layer is set to 2 nm or less, and a half bandwidth of an XRC in a (10-22) plane of the AlN-based group III nitride single crystal is 400 arcsec or less.

27. A method of growing a light-emitting device structure formed on a group III nitride single crystal, comprising the steps of:

growing an AlN-based group III nitride regrowth layer on the group III nitride single crystal;

growing a high-concentration n-type AlGaN layer on the AlN-based group III nitride regrowth layer;

growing a multi quantum well structure formed of an i-type or n-type doped Al_xGa_1-xN barrier layer and a well layer of an n-type or an i-type Al_yGa_1-yN layer (x>

y);

growing an undoped Al_xGa_1-xN;

growing a p-type Al_xGa_1-xN layer on the i-type Al_xGa_1-xN layer; and

growing an electron blocking layer between the i-type Al_xGa_1-xN layer and the p-type Al_xGa_1-xN layer formed on the i-type Al_xGa_1-xN layer, the electron blocking layer being formed of a p-type or i-type Al_zGa_1-zN layer (z>

x>

y, 0.95<

z≦

1) serving as an energy barrier for electrons form the n-type Al_xGa_1-xN layer.

28. The method of growing a light-emitting device structure according to 27, wherein each growth is performed at a low temperature of 1000°

C. to 1200°

C.

29. A method of growing a light-emitting device structure formed on a group III nitride single crystal, comprising the steps of:

growing a high-concentration n-type AlGaN layer on the AlN-based group III nitride regrowth layer;

growing a multi quantum well structure formed of an n-type or i-type group III nitride barrier layer and an n-type or i-type group III nitride well layer;

growing an i-type group III nitride final barrier layer;

growing a p-type group III nitride layer; and

growing an electron blocking layer formed between the i-type group III nitride final barrier layer and the p-type group III nitride layer, the electron blocking layer being formed of a p-type or i-type AN layer serving as an energy barrier for electrons from the i-type group III nitride final barrier layer.