Semiconductor laser, method of mounting semiconductor laser, semiconductor laser mounted structure, and optical disk system

• US 20060171435A1
• Filed: 10/31/2005
• Published: 08/03/2006
• Est. Priority Date: 11/01/2004
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Saito, Takahiro, Ohshima, Keiji, Nagahata, Kazunori
• Granted Patent: US 7,561,606 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: G11B 7/127 Lasers; Multiple laser arrays lasers per se H01S
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/85444 Gold (Au) as principal constituent
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01004 Beryllium [Be]
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 Silicon [Si]
• CPC Class Codes: H01L 2924/01023 Vanadium [V]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/0105 Tin [Sn]
• CPC Class Codes: H01L 2924/01074 Tungsten [W]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01S 5/02325 : Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/0234 : Up-side down mountings, e.g. Flip-chip, epi-side down mountings or junction down mountings
• CPC Class Codes: H01S 5/02345 : Wire-bonding
• CPC Class Codes: H01S 5/0237 : by soldering
• CPC Class Codes: H01S 5/04254 : characterised by the shape
• CPC Class Codes: H01S 5/06226 : Modulation at ultra-high frequencies
• 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 5/34333 : with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

An upper portion of a second clad layer and a contact layer are provided with grooves so as to form a ridge therebetween. An electrode is formed on the ridge. An insulation film is formed to extent on side surfaces of the ridge, on the inside of the grooves, and those portions of the contact layer which are located on the outside of the grooves. The thickness of those portions of the insulation film which are located on the contact layer in the areas on the outside of the grooves is set to be greater than at least the thickness of the electrode. Besides, a pad electrode is formed to cover the electrode and to extend on the insulation film on the upper side of the areas on the outside of the grooves. The upper surfaces of those portions of the pad electrode which are located on the upper side of the areas on the outside of the grooves are set to be above the upper surface of that portion of the pad electrode which is located on the upper side of the ridge.

Claims

1. A semiconductor laser comprising:

a substrate;

a first clad layer of a first conduction type on said substrate;

an active layer on said first clad layer;

a second clad layer of a second conduction type on said active layer; and

a contact layer of the second conduction type on said second clad layer, wherein

an upper portion of said second clad layer and said contact layer are provided with a pair of grooves in parallel to each other and at a predetermined interval so as to form a ridge therebetween;

an electrode on the second conduction type side is formed on said ridge;

an insulation layer is provided on side surfaces of said ridge, on the inside of said grooves, and on said contact layer in the areas on the outside of said grooves, and the thickness of those portions of said insulation layer which are located on said contact layer in said areas on the outside of said grooves is greater than at least the thickness of said electrode on the second conduction type side; and

a pad electrode is formed to cover said electrode on the second conduction type side and to extend on said insulation layer on the upper side of said areas on the outside of said grooves, and the upper surfaces of those portions of said pad electrode which are located on the upper side of said areas on the outside of said grooves are located above the upper surface of that portion of said pad electrode which is located on the upper side of said ridge.

2. The semiconductor laser as set forth in claim 1, wherein said first clad layer, said active layer, said second clad layer and said contact layer are comprised of a nitride based Group III-V compound semiconductor.

3. The semiconductor laser as set forth in claim 1, wherein said substrate is a conductive semiconductor substrate.

4. The semiconductor laser as set forth in claim 1, wherein said substrate is comprised of a nitride based Group III-V compound semiconductor.

5. The semiconductor laser as set forth in claim 1, wherein said substrate is a GaN substrate.

6. The semiconductor laser as set forth in claim 1, wherein an electrode on the first conduction type side is formed on the back side of said substrate.

7. A method of mounting a semiconductor laser on a sub-mount, said semiconductor laser comprising:

a substrate;

a first clad layer of a first conduction type on said substrate;

an active layer on said first clad layer;

a second clad layer of a second conduction type on said active layer; and

a contact layer of the second conduction type on said second clad layer, wherein

an upper portion of said second clad layer and said contact layer are provided with a pair of grooves in parallel to each other and at a predetermined interval so as to form a ridge therebetween;

an electrode on the second conduction type side is formed on said ridge;

an insulation layer is provided on side surfaces of said ridge, on the inside of said grooves, and on said contact layer in the areas on the outside of said grooves, and the thickness of those portions of said insulation layer which are located on said contact layer in said areas on the outside of said grooves is greater than at least the thickness of said electrode on the second conduction type side;

a pad electrode is formed to cover said electrode on the second conduction type side and to extend on said insulation layer on the upper side of said areas on the outside of said grooves, and the upper surfaces of those portions of said pad electrode which are located on the upper side of said areas on the outside of said grooves are located above the upper surface of that portion of said pad electrode which is located on the upper side of said ridge; and

said semiconductor laser is mounted on said sub-mount by soldering, during when the pattern of said solder is so determined that said solder is absent on the extension line of said ridge of said semiconductor laser, and positioning is so conducted that an end face on the front side of said semiconductor laser protrudes to the outside of said sub-mount.

8. A semiconductor laser mounted structure comprising a semiconductor laser mounted on a sub-mount, said semiconductor laser comprising:

a substrate;

a first clad layer of a first conduction type on said substrate;

an active layer on said first clad layer;

a second clad layer of a second conduction type on said active layer; and

a contact layer of the second conduction type on said second clad layer, wherein

an upper portion of said second clad layer and said contact layer are provided with a pair of grooves in parallel to each other and at a predetermined interval so as to form a ridge therebetween;

an electrode on the second conduction type side is formed on said ridge;

an insulation layer is provided on side surfaces of said ridge, on the inside of said grooves, and on said contact layer in the areas on the outside of said grooves, and the thickness of those portions of said insulation layer which are located on said contact layer in said areas on the outside of said grooves is greater than at least the thickness of said electrode on the second conduction type side;

a pad electrode is formed to cover said electrode on the second conduction type side and to extend on said insulation layer on the upper side of said areas on the outside of said grooves, and the upper surfaces of those portions of said pad electrode which are located on the upper side of said areas on the outside of said grooves are located above the upper surface of that portion of said pad electrode which is located on the upper side of said ridge; and

said semiconductor laser is mounted on said sub-mount by soldering, during when the pattern of said solder is so determined that said solder is absent on the extension line of said ridge of said semiconductor laser, and positioning is so conducted that an end face on the front side of said semiconductor laser protrudes to the outside of said sub-mount.

9. An optical disk system using a semiconductor laser as a light source, said semiconductor laser comprising:

a substrate;

a first clad layer of a first conduction type on said substrate;

an active layer on said first clad layer;

a second clad layer of a second conduction type on said active layer; and

a contact layer of the second conduction type on said second clad layer, wherein

an upper portion of said second clad layer and said contact layer are provided with a pair of grooves in parallel to each other and at a predetermined interval so as to form a ridge therebetween;

an electrode on the second conduction type side is formed on said ridge;

an insulation layer is provided on side surfaces of said ridge, on the inside of said grooves, and on said contact layer in the areas on the outside of said grooves, and the thickness of those portions of said insulation layer which are located on said contact layer in said areas on the outside of said grooves is greater than at least the thickness of said electrode on the second conduction type side; and

a pad electrode is formed to cover said electrode on the second conduction type side and to extend on said insulation layer on the upper side of said areas on the outside of said grooves, and the upper surfaces of those portions of said pad electrode which are located on the upper side of said areas on the outside of said grooves are located above the upper surface of that portion of said pad electrode which is located on the upper side of said ridge.