US5048036A
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Heterostructure laser with lattice mismatch
Assignee: Viavi Solutions Inc
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Filing: 1991-01-04
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Granted: 1991-09-10
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Expires: 2011-01-04
Abstract
Abstract Semiconductor heterostructure lasers having at least one lattice mismatched strain layer in the cladding proximate to the active region. Indium or phosphorus may be added in high concentration to form the strain layers. The strain layers may be spaced somewhat apart from the active region or may be adjacent to the active region. In either case, the strain layers decrease transparency current and increase differential gain.
Inventors
- 👤 Donald R. Scifres
- 👤 David F. Welch
- 👤 John Endriz
- 👤 William Streifer, deceased
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:52
CPC Classifications
B; B82; B82Y; B82Y20/00; H; H01; H01S; H01S5/00; H01S5/30; H01S5/34; H01S5/343; H01S5/34313; H01S5/32; H01S5/323; H01S5/32308; H01S5/0014; H01S5/0021; H01S5/305; H01S5/3201; H01S5/3403; H01S5/34306; H01S5/3432
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
50 words
In a semiconductor laser, a structure comprising, a substrate, and a multilayer semiconductor heterostructure disposed on said substrate, said heterostructure including an active region of at least one layer, at least one cladding layer of said heterostructure having a composition with a substantially different lattice constant than said active region.
Claim 2
Dependent Claim
50 words
In a semiconductor laser, a structure comprising, a substrate, and a multilayer semiconductor heterostructure disposed on said substrate, said heterostructure including an active region of at least one layer, at least one cladding layer of said heterostructure having a composition with a substantially different lattice constant than said active region.
Claim 3
Dependent Claim
28 words
The structure of claim 1 wherein said substrate is composed of material selected from the group consisting of GaAs, InP, GaP, GaAlAs, GaAsP, GaSb, InSb, InGaAsP and GaAlAsP.
Claim 4
Dependent Claim
30 words
The structure of claim 1 wherein said active region includes at least one quantum well layer composed of material selected from the group consisting of GaAs, InGaAs, InGaAsP and InP.
Claim 5
Dependent Claim
14 words
The structure of claim 1 wherein said at least one cladding layer contain phosphorus.
Claim 6
Dependent Claim
14 words
The structure of claim 1 wherein said cladding layer has a linearly graded composition.
Claim 7
Dependent Claim
13 words
The structure of claim 1 wherein said cladding layer has a nonuniform composition.
Claim 8
Dependent Claim
41 words
The structure of claim 1 wherein said heterostructure includes a thin strain layer formed in said cladding layer containing a concentration of phosphorus greater than 2%, whereby a lattice mismatch with said cladding layer of at least 0.2 percent is produced.
Claim 9
Dependent Claim
32 words
The structure of claim 7 wherein said thin strain layer is positioned sufficiently close to said active region so as to induce a strain in said active region, thereby altering the bandgap.
Claim 10
Dependent Claim
40 words
The structure of claim 1 wherein said active region is bounded by adjacent Al 1-y Gs y As 1-z P z strain layers, where z≧0.02 and 0≦y≦1, whereby strain is placed on said active region so as to increase gain.
Claim 11
Dependent Claim
30 words
The structure of claim 1 wherein said active region consists of multiple quantum wells separated by at least one barrier layer having a different lattice constant than said quantum wells.
Claim 12
Dependent Claim
118 words
In a semiconductor laser, a structure comprising: a substrate, and a multilayer semiconductor heterostructure disposed on said substrate, said heterostructure including an active region, cladding layers above and below said active region and at least one strain layer in one of said cladding layers, said active region and said cladding layers having lattice constants that substantially match one another, said strain layer having a lattice constant that differs from the lattice constant of said one of said cladding layers by at least 0.2% but not more than 4%, whereby a localized strain field is produced from lattice distortion at said strain layer, said strain layer having a thickness which is less than a critical thickness for dislocation generation.
Claim 13
Dependent Claim
118 words
In a semiconductor laser, a structure comprising: a substrate, and a multilayer semiconductor heterostructure disposed on said substrate, said heterostructure including an active region, cladding layers above and below said active region and at least one strain layer in one of said cladding layers, said active region and said cladding layers having lattice constants that substantially match one another, said strain layer having a lattice constant that differs from the lattice constant of said one of said cladding layers by at least 0.2% but not more than 4%, whereby a localized strain field is produced from lattice distortion at said strain layer, said strain layer having a thickness which is less than a critical thickness for dislocation generation.
Claim 14
Dependent Claim
18 words
The structure of claim 11 wherein said strain layer has a thickness on the order of 10 nm.
Claim 15
Dependent Claim
32 words
The structure of claim 11 wherein said strain layer is composed of InGaAlAsP in a GaAlAs cladding layer, said strain layer having a phosphorus content selected to provide said lattice constant difference.
Claim 16
Dependent Claim
19 words
The structure of claim 13 wherein said strain layer is composed of GaAs 1-z P z , where z≧0.02.
Claim 17
Dependent Claim
16 words
The structure of claim 11 wherein said strain layer is disposed adjacent to said active region.
Claim 18
Dependent Claim
31 words
The structure of claim 11 wherein said strain layer is disposed spaced away from said active region but proximate thereto, whereby said localized strain field is introduced into said active region.
Claim 19
Dependent Claim
19 words
The structure of claim 11 wherein said strain layer is disposed in said cladding layer below said active region.
Claim 20
Dependent Claim
23 words
The structure of claim 11 wherein a pair of strain layers is disposed in cladding layers both above and below said active region.
Claim 21
Dependent Claim
23 words
The structure of claim 18 wherein said pair of strain layers bound said active region and are disposed adjacent to said active region.
Claim 22
Dependent Claim
20 words
The structure of claim 11 wherein said active region consists of multiple quantum wells separated by lattice mismatched barrier layers.
Claim 23
Dependent Claim
74 words
In a semiconductor laser, a structure comprising, a substrate, and a multilayer semiconductor heterostructure disposed on said substrate, said heterostructure including an active region with at least one quantum well layer, and strain layers bounding said active region, said strain layers having a lattice constant that differs from said active region layers by at least 0.2%, each of said strain layers having a thickness which is less than a critical thickness for dislocation generation.
Claim 24
Dependent Claim
74 words
In a semiconductor laser, a structure comprising, a substrate, and a multilayer semiconductor heterostructure disposed on said substrate, said heterostructure including an active region with at least one quantum well layer, and strain layers bounding said active region, said strain layers having a lattice constant that differs from said active region layers by at least 0.2%, each of said strain layers having a thickness which is less than a critical thickness for dislocation generation.
Claim 25
Dependent Claim
11 words
The structure of claim 21 wherein said strain layers contain phosphorus.
Claim 26
Dependent Claim
13 words
The structure of claim 21 wherein said active region has multiple quantum wells.
Claim 27
Dependent Claim
18 words
The structure of claim 21 wherein each of said strain layers extends across the width of said heterostructure.
Claim 28
Dependent Claim
45 words
The structure of claim 21 wherein said strain layers have a composition which varies laterally in a periodic manner, whereby said lattice constant of said strain layers also varies laterally across said heterostructure in a periodic manner, said active region thereby having multiple laser emitters.
Claim 29
Dependent Claim
29 words
The structure of claim 21 wherein there are multiple laterally spaced apart strain layers bounding each side of said active region, whereby said active region has multiple laser emitters.
Claim 30
Dependent Claim
20 words
The structure of claim 21 wherein the active region consists of multiple quantum wells separated by lattice mismatched barrier regions.
Claim 31
Dependent Claim
22 words
The structure of claim 21 wherein barrier layers of said active region between multiple quantum wells of said active region contain phosphorus.
Claim 32
Dependent Claim
57 words
In a light emitting device, a structure comprising, a substrate, and a multilayer semiconductor heterostructure disposed on said substrate, said heterostructure including a light emitting region of at least one layer, at least one cladding layer of said heterostructure including a thin strained layer with a composition of a substantially different lattice constant than said active region.
Claim 33
Dependent Claim
57 words
In a light emitting device, a structure comprising, a substrate, and a multilayer semiconductor heterostructure disposed on said substrate, said heterostructure including a light emitting region of at least one layer, at least one cladding layer of said heterostructure including a thin strained layer with a composition of a substantially different lattice constant than said active region.
Claim 34
Dependent Claim
28 words
The structure of claim 29 wherein said substrate is composed of material selected from the group consisting of GaAs, InP, GaP, GaAlAs, GaAsP, GaSb, InSb, InGaAsP and GaAlAsP.
Claim 35
Dependent Claim
30 words
The structure of claim 29 wherein said active region includes at least one quantum well layer composed of material selected from the group consisting of GaAs, InGaAs, InGaAsP and InP.
Claim 36
Dependent Claim
14 words
The structure of claim 29 wherein said at least one cladding layer contain phosphorus.
Claim 37
Dependent Claim
38 words
The structure of claim 29 wherein said thin strained layer formed in said cladding layer contains a concentration of phosphorus greater than 2%, whereby a lattice mismatch with said cladding layer of at least 0.2 percent is produced.
Claim 38
Dependent Claim
27 words
The structure of claim 29 wherein said strained layer is positioned sufficiently close to said light emitting region so as to partially strain said light emitting region.
Claim 39
Dependent Claim
34 words
The structure of claim 29 wherein said active region is bounded by adjacent GaAs 1-z P z strain layers, where z≧0.02, whereby strain is placed on said active region so as to increase gain.
Claim 40
Dependent Claim
13 words
The structure of claim 29 wherein said cladding layer has a nonuniform composition.
Claim 41
Dependent Claim
20 words
The structure of claim 29 wherein said light emitting region consists of multiple quantum wells separated by strained barrier layers.
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