US5077266A
Expired / Lapsed
US
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Method of forming weak-link josephson junction, and superconducting device employing the junction
Assignee: Hitachi Ltd
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Filing: 1989-09-11
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Granted: 1991-12-31
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Expires: 2009-09-11
Abstract
Abstract A weak-link Josephson junction is of the type employing a thin film of an oxide superconductor, in which a crystal grain boundary produced reflecting an artificial crystal defect is utilized as the weak-link junction. The crystal grain boundary is formed concretely by a method in which atoms of different species are deposited on the predetermined part of the surface of a substrate, the predetermined part of the surface of a substrate is disturbed, or parts of different crystal face orientations are formed at the surface of a substrate, whereupon the superconducting thin film is epitaxially grown on the substrate, or by a method in which the predetermined part of the superconducting thin film, epitaxially grown on a substrate, is diffused with atoms of different species hampering a superconductivity, or the predetermined part of the superconducting thin film is disturbed, whereupon the superconducting thin film is annealed.
Inventors
- 👤 Kazumasa Takagi
- 👤 Tokuumi Fukazawa
- 👤 Yoshimi Kawanami
- 👤 Yuuichi Madokoro
- 👤 Katsuki Miyauchi
- 👤 Toshiyuki Aida
- 👤 Yukio Honda
- 👤 Masaaki Futamoto
- 👤 Masahiko Hiratani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:50
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/01; H10N60/0912; H10N60/0941; Y; Y10; Y10S; Y10S505/00; Y10S505/70; Y10S505/701; Y10S505/702; Y10S505/725; Y10S505/729
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
94 words
A method of forming a weak-link Josephson junction comprising the steps of: irradiating a substrate with a substance, thereby processing said substrate so as either to deposit said substance in the form of a line on a surface of said substrate or to damage the surface of said substrate in the form of a line by virtue of said substance, and epitaxially growing a thin film of an oxide superconductor on the processed substrate, thereby forming a crystal grain boundary on said line, said crystal grain boundary being used as a weak-link Josephson junction.
Claim 2
Independent Claim
94 words
A method of forming a weak-link Josephson junction comprising the steps of: irradiating a substrate with a substance, thereby processing said substrate so as either to deposit said substance in the form of a line on a surface of said substrate or to damage the surface of said substrate in the form of a line by virtue of said substance, and epitaxially growing a thin film of an oxide superconductor on the processed substrate, thereby forming a crystal grain boundary on said line, said crystal grain boundary being used as a weak-link Josephson junction.
Claim 3
Dependent Claim
27 words
A method of forming a weak-link Josephson junction as defined in claim 1, wherein said step of irradiating said substrate is performed by a focused ion beam.
Claim 4
Dependent Claim
32 words
A method of forming a weak-link Josephson junction as defined in claim 2, wherein said focused ion beam affords a dose within a range of 5×10 11 -5×10 18 /cm 2 .
Claim 5
Independent Claim
101 words
A method of forming a weak-link Josephson junction comprising the steps of: irradiating a thin film of an oxide superconductor, epitaxially grown on a substrate, with a substance for lowering a critical current density, thereby processing said thin film so as either to diffuse said substance in the form of a line within the thin oxide-superconductor film or to damage the oxide-superconductor thin film in the form of a line by virtue of said substance, and annealing the processed oxide-superconductor film, thereby forming a crystal grain boundary on said line, said crystal grain boundary being utilized as a weak-link Josephson junction.
Claim 6
Independent Claim
101 words
A method of forming a weak-link Josephson junction comprising the steps of: irradiating a thin film of an oxide superconductor, epitaxially grown on a substrate, with a substance for lowering a critical current density, thereby processing said thin film so as either to diffuse said substance in the form of a line within the thin oxide-superconductor film or to damage the oxide-superconductor thin film in the form of a line by virtue of said substance, and annealing the processed oxide-superconductor film, thereby forming a crystal grain boundary on said line, said crystal grain boundary being utilized as a weak-link Josephson junction.
Claim 7
Dependent Claim
26 words
A method of forming a weak-link Josephson junction as defined in claim 4, wherein the irradiation with said substance is performed by a focused ion beam.
Claim 8
Dependent Claim
32 words
A method of forming a weak-link Josephson junction as defined in claim 5, wherein said focused ion beam affords a dose within a range of 5×10 11 -5×10 18 /cm 2 .
Claim 9
Independent Claim
64 words
A method of forming a weak-link Josephson junction comprising the steps of: forming a substrate with sections having different crystal face orientations; epitaxially growing a thin film of an oxide superconductor on said substrate on which sections different in crystal face orientation are provided, thereby forming a crystal grain boundary between said sections, said crystal grain boundary being used as a weak-link Josephson junction.
Claim 10
Independent Claim
64 words
A method of forming a weak-link Josephson junction comprising the steps of: forming a substrate with sections having different crystal face orientations; epitaxially growing a thin film of an oxide superconductor on said substrate on which sections different in crystal face orientation are provided, thereby forming a crystal grain boundary between said sections, said crystal grain boundary being used as a weak-link Josephson junction.
Claim 11
Independent Claim
61 words
A method of forming a weak-link Josephson junction device comprising the steps of: providing a substrate; irradiating the substrate with a substance so as to form an irradiated region in the substrate; and epitaxially growing an oxide superconductor film on the irradiated region so that the oxide superconducting film has a boundary which has a microcrystal region on the irradiated region.
Claim 12
Independent Claim
61 words
A method of forming a weak-link Josephson junction device comprising the steps of: providing a substrate; irradiating the substrate with a substance so as to form an irradiated region in the substrate; and epitaxially growing an oxide superconductor film on the irradiated region so that the oxide superconducting film has a boundary which has a microcrystal region on the irradiated region.
Claim 13
Dependent Claim
14 words
The method as set forth in claim 8 wherein the substrate is a crystal.
Claim 14
Dependent Claim
17 words
The method as set forth in claim 9 wherein the irradiated region is a crystalline defect region.
Claim 15
Dependent Claim
16 words
The method as set forth in claim 8 wherein the irradiated region is a deposited region.
Claim 16
Dependent Claim
21 words
The method as set forth in claim 8 wherein the substance is atoms of different species from the oxide superconducting film.
Claim 17
Dependent Claim
18 words
The method as set forth in claim 8 further comprising the step of annealing the oxide superconducting film.
Claim 18
Dependent Claim
19 words
The method as set forth in claim 13 wherein said step of annealing is performed in an oxygen atmosphere.
Claim 19
Dependent Claim
21 words
The method as set forth in claim 2 wherein the focused ion beam is accelerated by not larger than 30 kV.
Claim 20
Dependent Claim
13 words
The method as set forth in claim 1 wherein the substrate comprises gallium.
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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) | 1994-12-30 | 1995-07-01 | 1995-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-30 | 1999-07-01 | 1999-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-30 | 2003-07-01 | 2003-12-31 | $7700.00 | Window Closed / Lapsed |