Nitride Semiconductor Laser Element

• US 20070217458A1
• Filed: 03/10/2005
• Published: 09/20/2007
• Est. Priority Date: 03/26/2004
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Kitano, Akira, Matsumura, Hiroaki, Katsuragi, Ken
• Granted Patent: US 7,995,634 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: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0422 with n- and p-contacts on the same side of the active layer
• CPC Class Codes: H01S 5/2063 obtained by particle bombardment
• CPC Class Codes: H01S 5/2205 comprising special burying or current confinement layers
• CPC Class Codes: H01S 5/2214 based on oxides or nitrides
• CPC Class Codes: H01S 5/2231 with inner confining structure only between the active layer and the upper electrode
• CPC Class Codes: H01S 5/227 Buried mesa structure ; Striped active layer
• 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 invention discloses that a nitride semiconductor laser element is able to comply with requirement of high-speed responsiveness by largely reducing the capacitance of the nitride semiconductor laser element. The nitride semiconductor laser element includes an n-type semiconductor layer, an active layer (205) and a p-type semiconductor layer each laminated on the main surface of the substrate (101) and comprising a nitride, wherein a striped ridge portion (2) is formed in the p-type semiconductor layer, and pn-junctions of the semiconductor layer in the peripheral region remote from the ridge portion are broken by ion implantation to form an insulative region (1) for reducing the capacitance of the element.

Claims

1. A nitride semiconductor laser element characterized by comprising:

a semiconductor layer of a first conductivity type, an active layer and a semiconductor layer of a second conductivity type, which are stacked one upon the other and each comprises a nitride;

a striped waveguide region for a laser light provided on the semiconductor layer of the second conductivity type; and

an insulative region for reducing the capacitance of the element, wherein a pn-junction of the semiconductor layer at a peripheral region remote from the waveguide region is broken.

3. The nitride semiconductor laser element according to claim 1, wherein the insulative region for reducing the capacitance of the element is a region formed by implanting ions from the surface of the semiconductor layer of the second conductivity type.

5. The nitride semiconductor laser element according to any one of claim 1, wherein the insulative region for reducing the capacitance of the element has an impurity peak concentration in the range from 1×

10¹⁸ to 5×

10²¹ atms/cm³.

6. The nitride semiconductor laser element according to any one of claim 1, wherein the insulative region for reducing the capacitance of the element has a peak of distribution of the impurity concentration in the depth direction in the range from 200 nm to 1 μ

m from the surface of the semiconductor layer of the second conductivity type.

9. The nitride semiconductor laser element according to claim 1, wherein the semiconductor laser element is a laser element for emitting bluish-purple light, and has responsiveness to input of pulse drive current of 1 ns or less.

2. A nitride semiconductor laser element characterized by comprising:

a semiconductor layer of a first conductivity type, an active layer and semiconductor layers of a second conductivity type, which are staked one upon the other and each comprises a nitride;

a striped waveguide region for a laser light provided on the semiconductor layer of the second conductivity type; and

an insulative region for reducing the capacitance of the element having no depletion layer in the semiconductor layer at a peripheral region remote from the waveguide region.

4. A nitride semiconductor laser element characterized by comprising:

a substrate;

a semiconductor layer of a first conductivity type, an active layer and a semiconductor layer of a second conductivity type, which are stacked on a main surface of the substrate and each comprises a nitride;

a striped waveguide region for a laser light provided on the semiconductor layer of the second conductivity type;

an embedded insulation film covering a side face of the waveguide region and a surface of the semiconductor layer of the second conductivity type;

a first electrode in contact with a surface of the waveguide region;

a protective insulation film covering at least a part of the embedded insulation film;

a second electrode substantially connected to the semiconductor layer of the first conductivity type; and

an insulative region for reducing the capacitance of the element, provided by converting at least a part of the semiconductor layer at a peripheral region remote from the waveguide region into a higher resistance one by ion implantation.

7. The nitride semiconductor laser element according to any one of claim 4, wherein the first electrode is formed in contact with the surface of the waveguide region so as to cover a part of the embedded insulation film, a pad electrode is formed in contact with the first electrode so as to cover a part of the protective insulation film, and the insulative region for reducing the capacitance of the element includes a region below the embedded insulation film.

8. The nitride semiconductor laser element according to claim 4, wherein the first electrode is formed in contact with the surface of the waveguide region so as to cover a part of the embedded insulation film, a pad electrode is formed in contact with the first electrode so as to cover a part of the protective insulation film, and the insulation region for reducing the capacitance of the element includes at least the first electrode or a region below the pad electrode.

10. A nitride semiconductor laser element characterized by comprising:

a semiconductor layer of a first conductivity type, an active layer and a semiconductor layer of a second conductivity type, which are staked one upon the other and each comprises a nitride;

a striped waveguide region of a laser light provided on the semiconductor layer of the second conductivity type; and

an insulative region having a withstand voltage of 10V or more at a region other than the waveguide region in the semiconductor of the second conductivity type.

11. A nitride semiconductor laser element characterized by comprising:

a semiconductor layer of a first conductivity type, an active layer and a semiconductor layer of a second conductivity type being different from the first conductivity type, which are stacked on a main surface of a substrate and each comprises a nitride; and

a striped waveguide region for a laser light provided on the semiconductor layer of the second conductivity type, wherein at least a part of the semiconductor layer of the second conductivity type serves as a region for reducing the capacitance of the element by being converted into the first conductivity type in a direction of thickness at a peripheral region remote from the waveguide region.

12. The nitride semiconductor laser element according to claim 11, having an npn structure in the peripheral region remote from the waveguide region, wherein the semiconductor layer of the first conductivity type is an n-type semiconductor layer, and the semiconductor layer of the second conductivity type is a p-type semiconductor layer.

13. The nitride semiconductor laser element according to claim 11, having a pnpn structure in the peripheral region remote from the waveguide region, wherein the semiconductor layer of the first conductivity type is an n-type semiconductor layer, and the semiconductor layer of the second conductivity type is a p-type semiconductor layer.

14. A bluish-purple light emitting laser element characterized by comprising:

a semiconductor layer of a first conductivity type, an active layer and a semiconductor layer of a second conductivity type, which are stacked one upon the other and each comprises a nitride; and

a striped waveguide region of a laser light provided on the semiconductor layer of the second conductivity type, wherein the element comprises an insulation region for reducing the capacitance of the element in a peripheral region remote from the waveguide region, and wherein responsiveness of the element with respect to input of a pulse drive current is 1 ns or less.