Semiconductor Laser Device and Manufacturing Method Thereof

• US 20070280318A1
• Filed: 12/06/2005
• Published: 12/06/2007
• Est. Priority Date: 12/08/2004
• Status: Active Grant

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Osaka Works of Sumitomo Electric Industries Limited
• Inventors: Matsubara, Hideki, Mori, Hiroki, Nakanishi, Fumitake, Yoshimoto, Susumu, Saitou, Hirohisa, Misaki, Takashi
• Granted Patent: US 8,605,769 B2
• Time in Patent Office: Days
• US Class Current: 372/43.10
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: H01S 2301/14 Semiconductor lasers with special structural design for lasing in a specific polarisation mode
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/11 Comprising a photonic bandgap structure
• CPC Class Codes: H01S 5/185 having only horizontal cavities, e.g. horizontal cavity surface-emitting lasers [HCSEL] comprising a photonic bandgap structure H01S5/11
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A semiconductor laser device (1) includes: a substrate (3) having a principal plane (3a); a photonic crystal layer (7) having an epitaxial layer (2a) of gallium nitride formed on substrate (3) in a direction in which principal plane (3a) extends and a low refractive index material (2b) having a refractive index lower than that of epitaxial layer (2a); an n-type clad layer (4) formed on substrate (3); a p-type clad layer (6) formed on substrate (3); an active layer (5) that is interposed between n-type clad layer (4) and p-type clad layer (6) and emits light when a carrier is injected thereinto; and a GaN layer (12) that covers a region directly on photonic crystal layer (7). Thus, the semiconductor laser device can be manufactured without fusion.

Claims

1. A semiconductor laser device, comprising:

a substrate having a principal plane;

a two-dimensional diffraction grating that is formed on said substrate in a direction in which said principal plane extends and has an epitaxial layer of gallium nitride and a low refractive index material having a refractive index lower than that of said epitaxial layer;

a first conductive-type clad layer formed on said substrate;

a second conductive-type clad layer formed on said substrate;

an active layer that is interposed between said first conductive-type clad layer and said second conductive-type clad layer and emits light when a carrier is injected thereinto; and

a layer containing gallium nitride that covers a region directly on said two-dimensional diffraction grating.

2. The semiconductor laser device according to claim 1, wherein said epitaxial layer has a plurality of holes, and said plurality of holes are filled with said low refractive index material to form diffraction grating points.

3. The semiconductor laser device according to claim 1, wherein said low refractive index material has a plurality of holes, and said plurality of holes are filled with gallium nitride, which forms said epitaxial layer, to form diffraction grating points.

4. The semiconductor laser device according to claim 1, wherein said layer containing gallium nitride covering a region directly on said two-dimensional diffraction grating and said epitaxial layer of gallium nitride constitute one layer or are layers successively epitaxially grown.

5. The semiconductor laser device according to claim 1, wherein said low refractive index material is made of at least one material selected from the group consisting of SiO2, MgF2, CaF2, BaF2, and LiF.

6. The semiconductor laser device according to claim 1, wherein said substrate is made of conductive gallium nitride or conductive silicon carbide.

7. A manufacturing method of a semiconductor laser device, comprising:

a step of forming a first conductive-type clad layer, an active layer and a second conductive-type clad layer on a substrate in this order;

a step of depositing a low refractive index material having a refractive index lower than that of gallium nitride in a predetermined pattern on said substrate;

an epitaxial layer forming step of forming an epitaxial layer of gallium nitride on said substrate after said step of depositing the low refractive index material; and

a step of growing a layer containing gallium nitride in a region directly on said low refractive index material along a principal plane of said substrate after said epitaxial layer forming step.

8. The manufacturing method of a semiconductor laser device according to claim 7, wherein said first conductive-type clad layer, said active layer and said second conductive-type clad layer are all epitaxially grown.

9. The manufacturing method of a semiconductor laser device according to claim 7, wherein said low refractive index material is made of at least one material selected from the group consisting of SiO2, MgF2, CaF2, BaF2, and LiF.

10. The manufacturing method of a semiconductor laser device according to claim 7, wherein said pattern of the low refractive index material is a pattern of a plurality of columns.

11. The manufacturing method of a semiconductor laser device according to claim 7, wherein said pattern of the low refractive index material is a pattern of a plurality of holes.

12. The manufacturing method of a semiconductor laser device according to claim 7, wherein said layer containing gallium nitride is formed using metal organic chemical vapor deposition in said step of growing the layer containing gallium nitride.

13. The manufacturing method of a semiconductor laser device according to claim 7, wherein said layer containing gallium nitride is formed in a state where the ambient pressure is equal to or lower than 90 kPa in said step of growing the layer containing gallium nitride.

14. A manufacturing method of a semiconductor laser device, comprising:

a step of epitaxially forming a first conductive-type clad layer, an active layer and a second conductive-type clad layer on a substrate in this order;

a step of forming an epitaxial layer of gallium nitride on said substrate;

a step of shaping said epitaxial layer into a two-dimensional diffraction grating; and

a step of growing a layer containing gallium nitride in a region directly on said two-dimensional diffraction grating along a principal plane of said substrate.

15. The manufacturing method of a semiconductor laser device according to claim 14, wherein a plurality of air holes are formed in said epitaxial layer in said step of shaping into the two-dimensional diffraction grating.

16. The manufacturing method of a semiconductor laser device according to claim 15, wherein said epitaxial layer is shaped into a plurality of columns in said step of shaping into the two-dimensional diffraction grating.

17. The manufacturing method of a semiconductor laser device according to claim 15, wherein said substrate is made of conductive gallium nitride or conductive silicon carbide.

18. A manufacturing method of a semiconductor laser device, comprising:

a step of epitaxially forming a first conductive-type clad layer, an active layer and a second conductive-type clad layer on a substrate in this order;

a step of forming an epitaxial layer of gallium nitride on said substrate;

a step of forming a plurality of holes in said epitaxial layer; and

a step of growing a layer containing gallium nitride in regions directly on said plurality of holes along a principal plane of said substrate using metal organic chemical vapor deposition.

19. The manufacturing method of a semiconductor laser device according to claim 18, wherein said layer containing gallium nitride is formed in a state where the ambient pressure is equal to or lower than 90 kPa in said step of growing the layer containing gallium nitride.

20. The manufacturing method of a semiconductor laser device according to claim 18, wherein said layer containing gallium nitride is formed in a state where the ambient pressure is equal to or higher than 10 kPa in said step of growing the layer containing gallium nitride.

21. The manufacturing method of a semiconductor laser device according to claim 18, further comprising a step of depositing a low refractive index material having a refractive index lower than that of gallium nitride in said plurality of holes after said step of forming the plurality of holes.

22. The manufacturing method of a semiconductor laser device according to claim 21, wherein said step of forming the plurality of holes includes a step of forming a resist on said epitaxial layer excluding the regions in which said plurality of holes are to be formed and a step of etching said epitaxial layer using said resist as a mask, and

said step of depositing the low refractive index material includes a step of depositing said low refractive index material in said plurality of holes and on said resist by vapor deposition and a step of removing said low refractive index material on said resist along with said resist.

23. The manufacturing method of a semiconductor laser device according to claim 21, wherein said low refractive index material is deposited by chemical vapor deposition in said step of depositing the low refractive index material.