Nitride semiconductor light-emitting device

• US 5,777,350 A
• Filed: 11/30/1995
• Issued: 07/07/1998
• Est. Priority Date: 12/02/1994
• Status: Expired due to Term

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Chemical Industries Limited (Nichia Corporation)
• Inventors: Nakamura, Shuji, Nagahama, Shinichi, Kiyoku, Hiroyuki, Iwasa, Naruhito
• Primary Examiner(s): Saadat, Mahshid D.
• Assistant Examiner(s): GUAY, JOHN FRANCIS
• Application Number:
  US08/565,101
• Time in Patent Office: 950 Days
• Field of Search: 257/76, 257/94, 257/96, 257/97, 257/14, 257/13, 257/103, 372/43, 372/45, 372/46
• US Class Current: 257/96
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• 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

A nitride semiconductor light-emitting device has an active layer of a single-quantum well structure or multi-quantum well made of a nitride semiconductor containing indium and gallium. A first p-type clad layer made of a p-type nitride semiconductor containing aluminum and gallium is provided in contact with one surface of the active layer. A second p-type clad layer made of a p-type nitride semiconductor containing aluminum and gallium is provided on the first p-type clad layer. The second p-type clad layer has a larger band gap than that of the first p-type clad layer. An n-type semiconductor layer is provided in contact with the other surface of the active layer.

Claims

1. A nitride semiconductor light-emitting device comprising:

an active layer of a quantum well structure comprising a nitride semiconductor containing indium and gallium, and having first and second main surfaces;

a first p-type clad layer comprising a p-type nitride semiconductor containing aluminum and gallium, and provided in contact with said second main surface of the active layer;

a second p-type clad layer comprising a p-type nitride semiconductor containing aluminum and gallium, having a larger band gap than that of said first p-type clad layer, and provided on said first p-type clad layer; and

an n-type semiconductor layer provided in contact with said first main surface of the active layer.

2. The device according to claim 1, wherein said first p-type clad layer has a thickness with in a range of 10 angstroms to 1.0 μ

m.

3. A nitride semiconductor light-emitting device comprising:

an active layer comprising of a quantum well structure comprising a nitride semiconductor containing indium and gallium, and having first and second main surfaces;

a first n-type clad layer made of an n-type nitride semiconductor containing aluminum and gallium or of an n-type GaN, and provided in contact with said first main surface of the active layer, said first n-type clad layer having a thickness within a range of 10 angstroms to 1.0 μ

m;

a second n-type clad layer comprising an n-type nitride semiconductor having a larger band gap than that of said first n-type clad layer, and provided on said first n-type clad layer; and

a p-type semiconductor layer provided in contact with said second main surface of the active layer.

4. The device according to claim 3, wherein said first n-type clad layer has a thickness within a range of 100 angstroms to 1.0 μ

m.

5. A nitride semiconductor light-emitting device comprising:

an active layer of a quantum well structure comprising a nitride semiconductor containing indium and gallium, and having first and second main surfaces;

a first n-type clad layer made of an n-type nitride semiconductor containing aluminum and gallium, or of an n-type GaN, and provided in contact with said first main surface of the active layer;

a second n-type clad layer comprising an n-type nitride semiconductor having a larger band gap than that of said first n-type clad layer, and provided on said first n-type clad layer;

a first p-type clad layer comprising a p-type nitride semiconductor containing aluminum and gallium, and provided in contact with said second main surface of the active layer; and

a second p-type clad layer comprising a p-type nitride semiconductor containing aluminum and gallium, having a larger band gap than that of said first p-type clad layer, and provided on said first p-type clad layer.

6. The device according to claim 5, wherein said first p-type clad layer has a thickness within a range of 10 angstroms to 1.0 μ

m.

7. The device according to claim 5, wherein said first n-type clad layer has a thickness within a range of 10 angstroms to 1.0 μ

m.

8. A nitride semiconductor light-emitting device comprising:

an active layer comprising a nitride semiconductor containing indium and gallium, and having first and second main surfaces;

a first n-type clad layer comprising an n-type nitride semiconductor not containing aluminum, and provided in contact with said first main surface of the active layer; and

a p-type clad layer comprising a p-type nitride semiconductor and having a surface region, at least said surface region comprising a p-type nitride semiconductor containing aluminum and gallium, said p-type clad layer being provided in contact with said second main surface of the active layer.

9. The device according to claim 8, wherein said active layer is of a quantum well structure.

10. The device according to claim 9, wherein said active layer is provided with a well layer comprising In_x Ga_1-x N where 0<

x<

1.

11. The device according to claim 10, wherein said active layer comprises a combination of a well layer comprising In_x Ga_1-x N where 0<

x<

1 with a barrier layer comprising In_x Ga_1-x N where 0<

x'"'"'<

1, and x=x'"'"'.

12. The device according to claim 8, wherein a total thickness of said active layer and said first n-type clad layer is 300 angstroms or more.

13. The device according to claim 8, wherein a total thickness of said active layer, said first n-type clad layer and said first p-type layer of said p-type clad layer is 300 angstroms or more.

14. The device according to claim 8, further comprising a second n-type clad layer comprising an n-type nitride semiconductor containing aluminum and gallium, and provided in contact with said first n-type clad layer.

15. The device according to claim 14, further comprising an n-type contact layer formed of an n-type GaN and provided in contact with said second n-type clad layer.

16. The device according to claim 8, further comprising an n-type contact layer formed of an n-type GaN and provided in contact with said first n-type clad layer.

17. The device according to claim 8, further comprising a p-type contact layer formed of a p-type GaN and provided in contact with said p-type clad layer.

18. The device according to claim 8, further comprising, as a light reflecting film, a first multi-layered film comprising at least two nitride semiconductor layers differing in composition, and provided on an outer side of said first n-type clad layer.

19. The device according to claim 18, further comprising an n-type contact layer formed of an n-type GaN and provided in contact with said first multi-layered film.

20. The device according to claim 8, further comprising, as a light reflecting film, a second multi-layered film comprising at least two nitride semiconductor layers differing in composition and provided on an outer side of said p-type clad layer.

21. The device according to claim 20, further comprising a p-type contact layer formed of a p-type GaN and provided in contact with said second multi-layered film.