Nitride semiconductor laser device and manufacturing method therefor

• US 20040238810A1
• Filed: 04/26/2004
• Published: 12/02/2004
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Ammono Sp. Z O.O.
• Original Assignee: Ammono Sp. Z O.O., Nichia Corporation
• Inventors: Kanbara, Yasuo, Doradzinski, Roman, Garczynski, Jerzy, Dwilinski, Robert, Sierzputowski, Leszek
• Granted Patent: US 7,057,211 B2
• Time in Patent Office: Days
• US Class Current: 257/12
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: C30B 7/005 Epitaxial layer growth
• CPC Class Codes: C30B 7/10 by application of pressure, e.g. hydrothermal processes
• CPC Class Codes: C30B 9/00 Single-crystal growth from melt solutions using molten solvents by normal or gradient freezing C30B11/00; by zone-melting C30B13/00; by crystal pulling C30B15/00; on immersed seed crystal C30B17/00; by liquid phase epitaxial growth C30B19/00; under a protective fluid C30B27/00
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/021 Silicon based substrates
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/0218 Substrates comprising semiconducting materials from other groups of the Periodic Table than the materials of the active layer
• CPC Class Codes: H01S 5/0281 Coatings made of semiconductor materials
• CPC Class Codes: H01S 5/164 with window regions comprising semiconductor material with a wider bandgap than the active layer
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/32025 non-polar orientation
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

The object of this invention is to provide a high-output type nitride semiconductor laser device comprising a pair of end faces of a resonator.

The nitride semiconductor laser device comprises an n-type nitride semiconductor layer or layers, a p-type nitride semiconductor layer or layers and a resonator, provided with an active layer comprising nitride semiconductor containing In therebetween, wherein at least light emitting end face of the resonator is covered with an end face film of single crystal Al_xGa_1−xN (0≦x≦1) formed at a low temperature not causing damage to the active layer comprising nitride semiconductor containing In.

Claims

1. A nitride semiconductor laser device which comprises an n-type nitride semiconductor layer or layers, a p-type nitride semiconductor layer or layers and a resonator, provided with an active layer comprising nitride semiconductor containing In therebetween,

wherein said resonator is provided with a pair of opposed end faces, and at least light emitting end face of said resonator is covered with an end face film of single crystal Al_xGa₁₋

xN (0≦

x≦

1) having larger band gap energy than that of the active layer and formed at a low temperature not causing that does not cause damage to said active layer.

2. The nitride semiconductor laser device according to claim 1, wherein a thickness of said end face film is from 50 angstrom to 1 μ

m.

3. The nitride semiconductor laser device according to claim 1, wherein said end face of the resonator is covered with the end face film of a single crystal comprising Al_x,Ga₁₋

xN (0≦

x≦

1) in a supercritical ammonia.

4. The nitride semiconductor laser device according to claim 3, wherein a p-type contact layer of said resonator is subject to at least masking and then said end face of said resonator is covered with the end face film of a single crystal comprising Al_x,Ga₁₋

xN (0≦

x≦

1) in a supercritical ammonia.

5. The nitride semiconductor laser device according to claim 3, characterized in that said end face film includes at least one of the elements of Group I (IUPAC, 1989).

6. The nitride semiconductor laser device according to claim 1, wherein said active layer includes a quantum well structure comprising at least one InGaN well layer or InAlGaN well layer.

7. The nitride semiconductor laser device according to claim 1, wherein said nitride semiconductor laser device is formed on the substrate selected from the group consisting of a GaN substrate, a sapphire substrate, a spinel substrate, a ZnO substrate, a SiC substrate, a ELO growth substrate and a substrate provided with a nitride semiconductor having an irregular surface.

8. The nitride semiconductor laser device according to claim 1, wherein said nitride semiconductor laser device is formed on C-plane, A-plane or M-plane of GaN substrate.

9. The nitride semiconductor laser device according to claim 1, wherein said nitride semiconductor laser device is formed on C-plane of GaN substrate and said end face film is grown on M-plane or A-plane.

10. The nitride semiconductor laser device according to claim 1, wherein said nitride semiconductor laser device is formed on A-plane of GaN substrate, and the light emitting face of said resonator is M-plane, on which said end face film is formed.

11. The nitride semiconductor laser device according to claim 1, wherein said nitride semiconductor laser device is formed on M-plane of GaN substrate grown in supercritical ammonia, and the light emitting face of said resonator is A-plane, on which said end face film is formed.

12. A method of manufacturing a nitride semiconductor laser device which comprises an n-type nitride semiconductor layer or layers, a p-type nitride semiconductor layer or layers and a resonator, provided with an active layer comprising nitride semiconductor containing In therebetween, the method comprises:

(1) etching or cleaving said laser device so that a pair of the opposed end faces of the resonator are formed;

(2) covering at least light emitting end face of said opposed end faces in the resonator with a film of a single crystal comprising Al_xGa<sub>1−

x</sub>N (0≦

x≦

1) formed at a low temperature that does not cause damage to said active layer.

13. The method for manufacturing a nitride semiconductor laser device according to claim 12, wherein during said second step said end face film is formed in a supercritical ammonia.

14. The method for manufacturing a nitride semiconductor laser device according to claim 13, wherein during the second step said end face film is formed after at least an upper surface of the resonator p-type contact layer is covered with a mask having a lower or same solubility in supercritical ammonia than that of a composition of the end face film.

15. The method for manufacturing a nitride semiconductor laser device according to claim 14, wherein said mask comprises a material selected from the group consisting of SiO, SiN, AIN, Mo and W.

16. The method for manufacturing a nitride semiconductor laser device according to claim 12, wherein said end face film is grown in the form of a single crystal in supercritical ammonia at a temperature of 900°

C. or less.

17. A nitride semiconductor laser device which comprises an n-type nitride semiconductor layer or layers, a p-type nitride semiconductor layer or layers and a resonator, provided with an active layer comprising nitride semiconductor containing In therebetween,

wherein said resonator is provided with a pair of opposed end faces, and at least light emitting end face of said resonator is covered with an end face film of single crystal Al_xGa₁₋

xN (0<

x<

1) having larger band gap energy than that of the active layer and including at least one element from Group I (IUPAC,

     1989), Li, K, Na or Cs which is formed at a low temperature that does not cause damage to said active layer.

18. The nitride semiconductor laser device according to claim 17, wherein said end face film of a single crystal comprising Al_xGa₁₋

xN (0<

x<

1) is formed in supercritical ammonia.