Laser diode

• US 8,774,245 B2
• Filed: 09/30/2010
• Issued: 07/08/2014
• Est. Priority Date: 10/29/2009
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Koda, Rintaro, Nakayama, Yusuke
• Primary Examiner(s): Niu, Xinning
• Application Number:
  US12/923,637
• Publication Number:
  US 20110103420A1
• Time in Patent Office: 1,377 Days
• Field of Search: 372/50.124
• US Class Current: 372/50.124
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 5/0014 Measuring characteristics or properties thereof measuring techniques per se G01J, G01K, G01N, G01R
• CPC Class Codes: H01S 5/0208 Semi-insulating substrates
• CPC Class Codes: H01S 5/04257 having positive and negative electrodes on the same side of the substrate
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/18358 containing spacer layers to adjust the phase of the light wave in the cavity
• CPC Class Codes: H01S 5/18369 based on dielectric materials
• CPC Class Codes: H01S 5/320275 semi-polar orientation
• 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: H01S 5/423 having a vertical cavity

Abstract

A laser diode with which high density crystal defect and surface roughness are able to be inhibited from being generated is provided. The laser diode includes a laminated body including an active layer and a current narrowing layer on a substrate. The substrate is an inclined substrate having an off-angle larger than 0 degrees in the direction of [1-100] from (0001) C plane.

Claims

1. A vertical cavity surface emitting laser diode comprising:

an N-type inclined GaN substrate in the vertical cavity surface emitting laser diode, said N-type inclined GaN substrate having an off-angle larger than 0 degrees in the direction of [1-100] from (0001) C plane;

a layer of N-type Al_x1Ga_1-x1N (0<

x1<

1) between said N-type inclined GaN substrate and a layer of N-type Al_x2Ga_2-x2N (0≦

x2<

x1), said layer of N-type Al_x1Ga_1-x1N (0<

x1<

1) touching said N-type inclined GaN substrate and said layer of N-type Al_x2Ga_2-x2N (0≦

x2<

x1);

an insulating layer between an active layer and a layer of P-type Al_x6Ga_1-x6N (0≦

x6<

1), said insulating layer touching said active layer and said layer of P-type Al_x6Ga_1-x6N (0≦

x6<

1);

an insulating layer aperture extending through said insulating layer, a portion of the layer of P-type Al_x6Ga_1-x6N (0≦

x6<

1) within said insulating layer aperture touching said active layer;

a layer of N-type Al_x3Ga_1-x3N (0≦

x3<

1) between said active layer and said layer of N-type Al_x2Ga_2-x2N (0≦

x2<

x1), said active layer touching said layer of N-type Al_x3Ga_1-x3N (0≦

x3<

1) and said insulating layer,

wherein said layer of N-type Al_x1Ga_1-x1N (0<

x1<

1) and said layer of N-type Al_x2Ga_2-x2N (0≦

x2<

x1) are in a lower DBR layer, light from said active layer being reflectible from said lower DBR layer and emissible through said insulating layer aperture.

2. The vertical cavity surface emitting laser diode according to claim 1, further comprising:

an upper electrode between an upper DBR layer and said layer of P-type Al_x6Ga_1-x6N (0≦

x6<

1), an upper electrode aperture being through said upper electrode.

3. The vertical cavity surface emitting laser diode according to claim 2, wherein said upper electrode touches said upper DBR layer and said layer of P-type Al_x6Ga_1-x6N (0≦

x6<

1).

4. The vertical cavity surface emitting laser diode according to claim 2, wherein said upper DBR layer in said upper electrode aperture touches said layer of P-type Al_x6Ga_1-x6N (0≦

x6<

1).

5. The vertical cavity surface emitting laser diode according to claim 2, wherein said light is emissible through said upper electrode aperture.

6. The vertical cavity surface emitting laser diode according to claim 5, wherein said light is emissible through said layer of P-type Al_x6Ga_1-x6N (0≦

x6<

1).

7. The vertical cavity surface emitting laser diode according to claim 1, wherein a well layer of undoped In_x4Ga_1-x4N (0<

x4<

1) and a buffer layer of undoped In_x5Ga_1-x5N (0<

x5<

x4) are in said active layer.

8. The vertical cavity surface emitting laser diode according to claim 1, wherein said active layer has a multiquantum well structure.

9. The vertical cavity surface emitting laser diode according to claim 1, wherein said lower DBR layer touches said lower spacer layer.

10. The vertical cavity surface emitting laser diode according to claim 1, wherein said lower spacer layer touches an electrode.

11. The vertical cavity surface emitting laser diode according to claim 1, wherein said N-type inclined GaN substrate is between said layer of N-type Al_x1Ga_1-x1N (0<

x1<

1) and a lower electrode, said a lower electrode touching said N-type inclined GaN substrate.

12. The vertical cavity surface emitting laser diode according to claim 1, wherein said layer of N-type Al_x2Ga_2-x2N (0≦

x2<

x1) is between said layer of N-type Al_x1Ga_1-x1N (0<

x1<

1) and a different layer of N-type Al_x1Ga_1-x1N (0<

x1<

1).

13. The vertical cavity surface emitting laser diode according to claim 1, wherein said layer of N-type Al_x1Ga_1-x1N (0<

x1<

1) is between said layer of N-type Al_x2Ga_2-x2N (0≦

x2<

x1) and a different layer of N-type Al_x2Ga_2-x2N (0≦

x2<

x1).

14. The vertical cavity surface emitting laser diode according to claim 1, wherein said off-angle is at not less than 0.1 degrees.

15. The vertical cavity surface emitting laser diode according to claim 1, wherein said off-angle is not less than 0.2 degrees.

16. The vertical cavity surface emitting laser diode according to claim 1, wherein said off-angle is not less than 0.5 degrees.

17. The vertical cavity surface emitting laser diode according to claim 1, wherein said low-refractive index layer of the lower DBR layer has a thickness of λ

₀/4n₁ and said high-refractive index layer of the lower DBR layer has a thickness of λ

₀/4n₂, with;

“

λ

₀”

being a wavelength of the light,

“

n₁”

being a refractive index of the low-refractive index layer of the lower DBR layer,

“

n₂”

being a refractive index of the high-refractive index layer of the lower DBR layer.