Nitride semiconductor device

• US 6,657,234 B1
• Filed: 03/16/2001
• Issued: 12/02/2003
• Est. Priority Date: 06/07/1999
• Status: Expired due to Term

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Tanizawa, Koji
• Primary Examiner(s): Jackson, Jerome
• Assistant Examiner(s): NGUYEN, JOSEPH H
• Application Number:
  US09/762,281
• Time in Patent Office: 991 Days
• Field of Search: 257/13-15, 257/79, 257/103, 257/613, 257/615, 257/94, 257/96
• US Class Current: 257/79
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 31/03042 characterised by the doping material
• CPC Class Codes: H01L 31/03046 including ternary or quaternary compounds, e.g. GaAlAs, InGaAs, InGaAsP
• CPC Class Codes: H01L 31/035236 Superlattices; Multiple quantum well structures
• CPC Class Codes: H01L 31/0735 comprising only AIIIBV compound semiconductors, e.g. GaAs/AlGaAs or InP/GaInAs solar cells
• CPC Class Codes: H01L 31/1852 comprising a growth substrate not being an AIIIBV compound
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• 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
• CPC Class Codes: H01S 5/305 characterised by the doping materials used in the laser structure
• CPC Class Codes: H01S 5/3086 doping of the active layer
• CPC Class Codes: H01S 5/309 doping of barrier layers that confine charge carriers in the laser structure, e.g. the barriers in a quantum well structure barriers in quantum wells per se H01S5/3407
• CPC Class Codes: H01S 5/3407 characterised by special barrier layers
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials

Abstract

An nitride semiconductor device for the improvement of lower operational voltage or increased emitting output, comprises an active layer comprising quantum well layer or layers and barrier layer or layers between n-type nitride. semiconductor layers and p-type nitride semiconductor layers, wherein said quantum layer in said active layer comprises InxGa1−xN (0<x<1) having a peak wavelength of 450 to 540 nm and said active layer comprises laminating layers of 9 to 13, in which at most 3 layers from the side of said n-type nitride semiconductor layers are doped with an n-type impurity selected from the group consisting of Si, Ge and Sn in a range of 5×10¹⁶ to 2×10¹⁸/cm³.

Claims

1. A nitride semiconductor device which comprises an active layer containing an n-type impurity and comprising a quantum well layer or layers and a barrier layer or layers between n-type nitride semiconductor layers and p-type nitride semiconductor layers, wherein at least said quantum well layer at the proximate side in said active layer to said n-type nitride semiconductor layers is doped with an n-type impurity and wherein at least said quantum well layer at the proximate side in said active layer to said p-type nitride semiconductor layers is not doped with an n-type impurity.

2. A nitride semiconductor device according to claim 1, wherein said active layer is a MQW structure having (i) laminated layers and at least one of 1st to j-th layers counting from the side proximate to said n-type nitride semiconductor layers is doped with n-type impurity;

wherein

3. A nitride semiconductor device according to claim 1, wherein said active layer contains an n-type impurity and comprises an MQW structure comprising quantum well layers and barrier layers between n-type nitride semiconductor layers and p-type nitride semiconductor layers, wherein at least said quantum well layer at the proximate side in said active layer to said n-type nitride semiconductor layers is doped with an n-type impurity and at least said quantum well layer at the proximate side in said active layer to said n-type nitride semiconductor layers is doped with an n-type impurity, and

wherein said barrier layer and/or said quantum well layer at the proximate side to said p-type semiconductor layers are not doped with n-type impurity.

4. A nitride semiconductor device according to claim 1, wherein said active layer contains an n-type impurity and comprises an MQW structure comprising quantum well layers and barrier layers between n-type nitride semiconductor layers and p-type nitride semiconductor layers, wherein at least said quantum well layer and said barrier layer at the proximate side in said active layer to said n-type nitride semiconductor layers are doped with n-type impurity and wherein at least said quantum well layer and said barrier layer at the proximate side in said active layer to said p-type nitride semiconductor layers are not doped with n-type impurity.

5. A nitride semiconductor device according to claim 1, wherein said active layer is a MQW structure comprising a quantum well layer and barrier layer pairs sandwiching said quantum well layer, wherein said barrier layer at the proximate side to said n-type nitride semiconductor layers are doped with n-type impurity, and said quantum well layer and said barrier layer at the proximate side to said p-type semiconductor nitride layers are not doped with n-type impurity.

6. A nitride semiconductor device according to claim 1, wherein said active layer comprises 9 to 15 layers, at most 4 layers of which, counting from the proximate side to said n-type semiconductor layers, are doped with n-type impurity.

7. A nitride semiconductor device according to claim 1, wherein said quantum well layers in said active layer comprises In_xGa₁₋

xN (0<

x<

1) which is able to emit or receive a peak wavelength belonging to a range of 470 to 530 nm.

8. A nitride semiconductor device according to claim 1, wherein said n-type impurity is selected from the group consisting of Si, Ge and Sn.

9. A nitride semiconductor device according to claim 8, wherein said n-type impurity is Si.

10. A nitride semiconductor device according to claim 1, wherein said n-type impurity content of said active layer is lower than that of said n-type nitride semiconductor layers.

11. A nitride semiconductor device according to claim 1, wherein the n-type impurity content of the active layer decreases as the distance from said n-type nitride semiconductor layers increases.

12. A nitride semiconductor device according to claim 1, wherein the n-type impurity content of said active layer is in a range of 5×

10¹⁶ to 2×

10¹⁸/cm³.

13. A nitride semiconductor device according to claim 12, wherein the n-type impurity content of said barrier layer in said active layer is in a range of 5×

10¹⁶ to 2×

10¹⁸/cm³.

14. A nitride semiconductor device according to claim 12, wherein the n-type impurity content of said quantum well layer in said active layer is in a range of 5×

10¹⁶ to 2×

10¹⁸/cm³.

15. A nitride semiconductor device according to claim 9, wherein the n-type impurity content of said barrier layer in said active layer is in a range of 5×

10¹⁶ to 2×

10¹⁸/cm³, whereas the n-type impurity content of said quantum well layer in said active layer is in a range of 5×

10¹⁶ to 2×

10¹⁸/cm³ and lower than that of said barrier layer.

16. A nitride semiconductor device according to claim 9, wherein the n-type impurity content of said barrier layer in said active layer is in a range of 5×

10^{16 to} 2×

10¹⁸/cm³, whereas the n-type impurity content of said quantum well layer in said active layer is less than 5×

10¹⁶ to 2×

10¹⁸/cm³ and lower than that of said barrier layer.

17. A nitride semiconductor device according to claim 2, wherein the thickness of said barrier layer or quantum well layer close or proximate to said n-type semiconductor layers is larger than that of said barrier layer or quantum well layer close or proximate to said p-type semiconductor layers.

18. A nitride semiconductor device according to claim 2, wherein the thickness of said barrier layer or quantum well layer close or proximate to said n-type semiconductor layers is smaller than that of said barrier layer or quantum well layer close or proximate to said p-type semiconductor layers.

31. A nitride semiconductor emitting device according to claim 6, wherein the first and second layers from the side of said n type nitride semiconductor layers are doped with the n type impurity.

19. A nitride semiconductor emitting device which comprises an active layer comprising quantum well layer or layers and barrier layer or layers between n-type nitride semiconductor layers and p-type nitride semiconductor layers, wherein said quantum layer in said active layer comprises InxGa1−

xN (0<

x<

1) having a peak wavelength of 450 to 540 nm and said active layer comprises laminating layers of 9 to 13, in which at most 3 layers from the side of said n-type nitride semiconductor layers are doped with an n-type impurity selected from the group consisting of Si, Ge and Sn at a range of 5×

10¹⁶ to 2×

10¹⁸/cm³, and the other layers are not doped with an n-type impurity.

20. A nitride semiconductor emitting device according to claim 19, wherein the thickness of said barrier layer or quantum well layer close or proximate to said n-type semiconductor layers is larger than that of said barrier layer or quantum well layer proximate to said p-type semiconductor layers.

21. A nitride semiconductor emitting device according to claim 19, wherein the thickness of said barrier layer or quantum well layer close or proximate to said n-type semiconductor layers is smaller than that of said barrier layer or quantum well layer close or proximate to said p-type semiconductor layers.

22. A nitride semiconductor emitting device according to claim 19, wherein said n-type impurity is Si.

23. A nitride semiconductor emitting device according to claim 19, wherein said quantum well layer in said active layer comprises In_xGa₁₋

xN (0<

x<

1) having a peak wavelength of 490 to 510 nm.

24. A nitride semiconductor emitting device according to claim 23, wherein said barrier layer in said active layer comprises In_yGa₁₋

yN (0≦

y<

1, y<

x).

25. A nitride semiconductor emitting device according to claim 19, wherein said active layer comprises an MQW of In_xGa₁₋

xN (0<

x<

1)/In_yGa<sub>1−

y</sub>N (0≦

y<

1, y<

x) lamination and is formed on an n-type multi-layer.

26. A nitride semiconductor emitting device according to claim 25, wherein said multi-layer is a buffer super lattice layer undoped with n-type impurity and comprising In_zGa₁₋

zN (0<

z<

1)/GaN lamination or Al_wGa<sub>1−

w</sub>N (0<

w<

1)/GaN lamination.

27. A nitride semiconductor emitting device according to claim 26, wherein said GaN layer of said buffer super lattice layer has a thickness of less than 70 Å

and said barrier layer of said active layer has a thickness of more than 70 Å

.

28. A nitride semiconductor emitting device according to claim 27, wherein said multi-layer are doped with n-impurity and comprises lamination of GaN layer and a layer selected from the group consisting of a In_zGa₁₋

z (0<

z<

1, z<

y) layer having a larger band gap energy than that of said quantum well layer and a Al_wGa_wN (0<

w<

1) layer.

29. A nitride semiconductor emitting device according to claim 28, wherein said n-type impurity for doping into said active layer and said n-type clad layer is Si and the Si content of said active layer is in a range of 5×

10¹⁶ to 2×

10¹⁸/cm³whereas the Si content of said n-clad layer is in a range of more than 5×

10¹⁷/cm³ and larger than that of said active layer.

30. A nitride semiconductor emitting device according to claim 19, wherein the first layer form the side of said n type nitride semiconductor layers is doped with the n type impurity and the other layers are not doped with the n type impurity.