Patent US5656539A successfully refreshed from Google Patents.
US5656539A
Expired / Lapsed
US
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Method of fabricating a semiconductor laser
Assignee: Mitsubishi Electric Corp
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Filing: 1995-03-07
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Granted: 1997-08-12
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Expires: 2015-03-07
Abstract
Abstract A method of fabricating a semiconductor laser includes forming a mask having a stripe opening in a <011> direction on a {100} surface of a first conductivity type substrate, and growing a double-heterojunction structure including a first conductivity type cladding layer, an active layer, and a second conductivity type cladding layer on the {100} surface using the mask, thereby producing a stripe-shaped ridge in which the active layer and the first conductivity type lower cladding layer are covered with the second conductivity type upper cladding layer. The stripe-shaped ridge has an ordinary mesa-shaped cross-section in a direction perpendicular to the stripe direction and a symmetrical hexagonal cross-section in the stripe direction. In this method, since the conventional selective etching for forming the ridge is dispensed with, the processing precision of the ridge is improved. Further, the second conductivity type cladding layer and the active layer grown on the side surfaces of the first conductivity type cladding layer are very thin and have low dopant incorporating efficiencies, so that portions of the first conductivity type cladding layer grown at the side surfaces of the ridge have high resistivity, and reactive current is blocked by these high-resistance portions.
Inventors
- 👤 Takashi Motoda
- 👤 Manabu Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:02
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/20; H01S5/22; H01S5/227; H01S5/10; H01S5/16; H01S5/164; H01S5/2205; H01S5/2222; H01S5/2227; H01S5/2272; Y; Y10; Y10S; Y10S117/00; Y10S117/913
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
154 words
In a method of fabricating a semiconductor laser: forming a selective growth mask having a stripe-shaped opening extending in a <011> direction on and exposing a {100} surface of a semiconductor substrate in the opening, the substrate having a first conductivity type; and using the selective growth mask, successively growing an AlGaInP lower cladding layer of the first conductivity type and a GaInP active layer having a band gap energy on the {100} surface of the substrate, thereby forming part of a stripe-shaped ridge having side surfaces, and growing an AlGaInP upper cladding layer of the second conductivity type simultaneously on the active layer and on the side surfaces of the stripe-shaped ridge, thereby covering side surfaces of the first conductivity type lower cladding layer and of the active layer, the stripe-shaped ridge having a mesa-shaped cross-section in a direction perpendicular to the stripe direction and a symmetrical hexagonal cross-section along the stripe direction.
Claim 2
Dependent Claim
154 words
In a method of fabricating a semiconductor laser: forming a selective growth mask having a stripe-shaped opening extending in a <011> direction on and exposing a {100} surface of a semiconductor substrate in the opening, the substrate having a first conductivity type; and using the selective growth mask, successively growing an AlGaInP lower cladding layer of the first conductivity type and a GaInP active layer having a band gap energy on the {100} surface of the substrate, thereby forming part of a stripe-shaped ridge having side surfaces, and growing an AlGaInP upper cladding layer of the second conductivity type simultaneously on the active layer and on the side surfaces of the stripe-shaped ridge, thereby covering side surfaces of the first conductivity type lower cladding layer and of the active layer, the stripe-shaped ridge having a mesa-shaped cross-section in a direction perpendicular to the stripe direction and a symmetrical hexagonal cross-section along the stripe direction.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein the first conductivity type substrate comprises GaAs.
Claim 4
Dependent Claim
80 words
The method of claim 1 including: after formation of the stripe-shaped ridge, removing the selective growth mask and growing a current blocking layer comprising a material having a band gap energy larger than the band gap energy of the active layer on the {100} surface of the substrate where the ridge is absent to a thickness at least reaching the top of the ridge; and forming resonator facets of the semiconductor laser in regions where the active layer is present.
Claim 5
Dependent Claim
12 words
The method of claim 3 wherein the current blocking layer comprises AlGaInP.
Claim 6
Dependent Claim
59 words
The method of claim 1 including growing a p type cladding layer as the second conductivity type cladding layer while supplying a gas mixture including a p type dopant source and an n type dopant source in a ratio so that portions of the p type cladding layer grown at the opposite sides of the ridge have high resistivity.
Claim 7
Dependent Claim
59 words
The method of claim 1 including growing a p type cladding layer as the first conductivity type cladding layer while supplying a gas mixture including a p type dopant source and an n type dopant source in a ratio so that portions of the p type cladding layer grown at the opposite sides of the ridge have high resistivity.
Claim 8
Dependent Claim
13 words
The method of claim 7 wherein the first conductivity type substrate comprises GaAs.
Claim 9
Dependent Claim
155 words
In a method of fabricating a semiconductor laser: forming a selective growth mask having a stripe-shaped opening extending in a <011> direction on and exposing a {100} surface of a semiconductor substrate in the opening, the substrate having a first conductivity type; and using the selective growth mask, successively growing an AlGaInP lower cladding layer having the first conductivity type and a GaInP active layer having a band gap energy on the {100} surface of the substrate, thereby forming part of a stripe-shaped ridge having side surfaces, and growing an AlGaInP upper cladding layer of the second conductivity type simultaneously on the active layer and on the side surfaces of the stripe-shaped ridge, thereby covering side surfaces of the first conductivity type lower cladding layer and of the active layer, the stripe-shaped ridge having a symmetrical hexagonal cross-section in a direction perpendicular to the stripe direction and an isosceles trapezoidal cross-section along the stripe direction.
Claim 10
Dependent Claim
155 words
In a method of fabricating a semiconductor laser: forming a selective growth mask having a stripe-shaped opening extending in a <011> direction on and exposing a {100} surface of a semiconductor substrate in the opening, the substrate having a first conductivity type; and using the selective growth mask, successively growing an AlGaInP lower cladding layer having the first conductivity type and a GaInP active layer having a band gap energy on the {100} surface of the substrate, thereby forming part of a stripe-shaped ridge having side surfaces, and growing an AlGaInP upper cladding layer of the second conductivity type simultaneously on the active layer and on the side surfaces of the stripe-shaped ridge, thereby covering side surfaces of the first conductivity type lower cladding layer and of the active layer, the stripe-shaped ridge having a symmetrical hexagonal cross-section in a direction perpendicular to the stripe direction and an isosceles trapezoidal cross-section along the stripe direction.
Claim 11
Dependent Claim
80 words
The method of claim 7 including: after formation of the stripe-shaped ridge, removing the selective growth mask and growing a current blocking layer comprising a material having a band gap energy larger than the band gap energy of the active layer on the {100} surface of the substrate where the ridge is absent to a thickness at least reaching the top of the ridge; and forming resonator facets of the semiconductor laser in regions where the active layer is absent.
Claim 12
Dependent Claim
12 words
The method of claim 9 wherein the current blocking layer comprises AlGaInP.
Claim 13
Dependent Claim
59 words
The method of claim 7 including growing a p type cladding layer as the second conductivity type cladding layer while supplying a gas mixture including a p type dopant source and an n type dopant source in a ratio so that portions of the p type cladding layer grown at the opposite sides of the ridge have high resistivity.
Claim 14
Dependent Claim
59 words
The method of claim 7 including growing a p type cladding layer as the first conductivity type cladding layer while supplying a gas mixture including a p type dopant source and an n type dopant source in a ratio so that portions of the p type cladding layer grown at the opposite sides of the ridge have high resistivity.
Claim 15
Dependent Claim
156 words
In a method of fabricating a semiconductor laser: forming a selective growth mask having a stripe-shaped opening extending in a <001> direction on and exposing a {100} surface of a semiconductor substrate in the opening, the substrate having a first conductivity type; and using the selective growth mask, successively growing an AlGaInP lower cladding layer having the first conductivity type and a GaInP active layer having a band gap energy on the {100} surface of the substrate, thereby forming part of a stripe-shaped rectangular ridge having side surfaces, and growing an AlGaInP upper cladding layer of the second conductivity type simultaneously on the active layer and on the side surfaces of the stripe-shaped ridge, thereby covering side surfaces of the first conductivity type lower cladding layer and of the active layer, the stripe-shaped ridge having a symmetrical hexagonal cross-section in a direction perpendicular to the stripe direction and an isosceles trapezoidal cross-section along the stripe direction.
Claim 16
Dependent Claim
156 words
In a method of fabricating a semiconductor laser: forming a selective growth mask having a stripe-shaped opening extending in a <001> direction on and exposing a {100} surface of a semiconductor substrate in the opening, the substrate having a first conductivity type; and using the selective growth mask, successively growing an AlGaInP lower cladding layer having the first conductivity type and a GaInP active layer having a band gap energy on the {100} surface of the substrate, thereby forming part of a stripe-shaped rectangular ridge having side surfaces, and growing an AlGaInP upper cladding layer of the second conductivity type simultaneously on the active layer and on the side surfaces of the stripe-shaped ridge, thereby covering side surfaces of the first conductivity type lower cladding layer and of the active layer, the stripe-shaped ridge having a symmetrical hexagonal cross-section in a direction perpendicular to the stripe direction and an isosceles trapezoidal cross-section along the stripe direction.
Claim 17
Dependent Claim
13 words
The method of claim 13 wherein the first conductivity type substrate comprises GaAs.
Claim 18
Dependent Claim
80 words
The method of claim 13 including: after formation of the stripe-shaped ridge, removing the selective growth mask and growing a current blocking layer comprising a material having a band gap energy larger than the band gap energy of the active layer on the {100} surface of the substrate where the ridge is absent to a thickness at least reaching the top of the ridge; and forming resonator facets of the semiconductor laser in regions where the active layer is absent.
Claim 19
Dependent Claim
12 words
The method of claim 15 wherein the current blocking layer comprises AlGaInP.
Claim 20
Dependent Claim
59 words
The method of claim 13 including growing a p type cladding layer as the second conductivity type cladding layer while supplying a gas mixture including a p type dopant source and an n type dopant source in a ratio so that portions of the p type cladding layer grown at the opposite sides of the ridge have high resistivity.
Claim 21
Dependent Claim
59 words
The method of claim 13 including growing a p type cladding layer as the first conductivity type cladding layer while supplying a gas mixture including a p type dopant source and an n type dopant source in a ratio so that portions of the p type cladding layer grown at the opposite sides of the ridge have high resistivity.
Claim 22
Dependent Claim
25 words
The method of claim 13 including, after formation of the stripe-shaped ridge, forming resonator facets of the semiconductor laser at opposite ends of the ridge.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-08-11 | 2001-02-10 | 2001-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-11 | 2005-02-10 | 2005-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-11 | 2009-02-10 | 2009-08-12 | $7700.00 | Window Closed / Lapsed |