US4358783A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Superconducting thin films
Assignee: AT&T Inc
•
Filing: 1980-09-30
•
Granted: 1982-11-09
•
Expires: 2000-09-30
Abstract
Abstract This invention relates to granular metal and metal oxide superconducting films formed by ion beam sputter deposition. Illustratively, the films comprise irregularly shaped, randomly oriented, small lead grains interspersed in an insulating lead oxide matrix. The films are hillock-resistant when subjected to thermal cycling and exhibit unusual Josephson-type switching characteristics. Depending on the oxygen content, a film may behave in a manner similar to that of a plurality of series connected Josephson junctions, or the film may have a voltage difference in a direction parallel to a major surface of the film that is capable of being switched from zero voltage difference to a finite voltage difference in response to a current larger than the critical current.
Inventors
- 👤 Arthur F. Hebard
- 👤 Joanna M. Vandenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:26
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/80; H10N60/85; H10N60/01; H10N60/0912; H10N60/20; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/873; Y10S505/874
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
59 words
A superconducting device including: a thin superconducting film; and means for applying an electric current to said film; said film comprising; irregularly shaped small metal grains having a plurality of orientations; and an insulating matrix, in which said grains are interspersed, comprising at least one oxide of said metal; whereby said film is hillock-resistant when subjected to thermal cycling.
Claim 2
Dependent Claim
59 words
A superconducting device including: a thin superconducting film; and means for applying an electric current to said film; said film comprising; irregularly shaped small metal grains having a plurality of orientations; and an insulating matrix, in which said grains are interspersed, comprising at least one oxide of said metal; whereby said film is hillock-resistant when subjected to thermal cycling.
Claim 3
Dependent Claim
17 words
The device of claim 1 wherein said insulating matrix includes at least two oxides of said metal.
Claim 4
Dependent Claim
19 words
The device of claim 1 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 5
Dependent Claim
18 words
The device of claim 2 or 3 wherein said oxides include PbO and Pb 3 O 4 .
Claim 6
Dependent Claim
91 words
A superconducting device including: a superconducting film; and means for applying an electric current to said film; said device being formed by a process including the steps of: partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said evacuable chamber, whereby said film is hillock-resistant when subjected to thermal cycling; and forming electrode means for applying current to said film.
Claim 7
Dependent Claim
91 words
A superconducting device including: a superconducting film; and means for applying an electric current to said film; said device being formed by a process including the steps of: partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said evacuable chamber, whereby said film is hillock-resistant when subjected to thermal cycling; and forming electrode means for applying current to said film.
Claim 8
Dependent Claim
20 words
The superconducting device of claim 5 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 9
Dependent Claim
90 words
A Josephson junction device comprising: a first superconducting film; a film contiguous with said first film forming a tunnel barrier; and a second superconducting film contiguous with said tunnel barrier; at least one of said first and second superconducting films comprising: irregularly shaped small metal grains having a plurality of orientations; and an insulating matrix, in which said grains are interspersed, comprising at least one oxide of said metal, whereby the film forming at least one of said first and second superconducting films is hillock-resistant when subjected to thermal cycling.
Claim 10
Dependent Claim
90 words
A Josephson junction device comprising: a first superconducting film; a film contiguous with said first film forming a tunnel barrier; and a second superconducting film contiguous with said tunnel barrier; at least one of said first and second superconducting films comprising: irregularly shaped small metal grains having a plurality of orientations; and an insulating matrix, in which said grains are interspersed, comprising at least one oxide of said metal, whereby the film forming at least one of said first and second superconducting films is hillock-resistant when subjected to thermal cycling.
Claim 11
Dependent Claim
20 words
The Josephson device of claim 7 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 12
Dependent Claim
114 words
A Josephson junction device comprising: a first superconducting film; a film contiguous with said first film forming a tunnel barrier; and a second superconducting film contiguous with said tunnel barrier; at least one of said first and second sueprconducting films being produced by a process including the steps of; partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; and directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising metal and oxide of said metal on an insulating body within said evacuable chamber; whereby said film forming at least one of said first and second superconducting films is hillock-resistant when subjected to thermal cycling.
Claim 13
Dependent Claim
114 words
A Josephson junction device comprising: a first superconducting film; a film contiguous with said first film forming a tunnel barrier; and a second superconducting film contiguous with said tunnel barrier; at least one of said first and second sueprconducting films being produced by a process including the steps of; partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; and directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising metal and oxide of said metal on an insulating body within said evacuable chamber; whereby said film forming at least one of said first and second superconducting films is hillock-resistant when subjected to thermal cycling.
Claim 14
Dependent Claim
19 words
The device of claim 9 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 15
Dependent Claim
119 words
A superconducting device including: a thin superconducting film having a pair of substantially parallel spaced-apart major surfaces; and electrode means for applying an electric current to said film in a direction parallel to said surfaces; said film comprising: a string of n irregularly shaped clusters of irregularly shaped small metal grains, said grains having a plurality of orientations and being interspersed in a metal oxide insulating matrix, each cluster having a width substantially coextensive with the width of said film; and (n-1) barriers comprising at least one oxide of said metal to separate adjacent clusters, whereby; the current-voltage characteristic of said device is substantially indistinguishable from the current-voltage characteristic of a plurality of (n-1) series connected Josephson tunnel junctions.
Claim 16
Dependent Claim
119 words
A superconducting device including: a thin superconducting film having a pair of substantially parallel spaced-apart major surfaces; and electrode means for applying an electric current to said film in a direction parallel to said surfaces; said film comprising: a string of n irregularly shaped clusters of irregularly shaped small metal grains, said grains having a plurality of orientations and being interspersed in a metal oxide insulating matrix, each cluster having a width substantially coextensive with the width of said film; and (n-1) barriers comprising at least one oxide of said metal to separate adjacent clusters, whereby; the current-voltage characteristic of said device is substantially indistinguishable from the current-voltage characteristic of a plurality of (n-1) series connected Josephson tunnel junctions.
Claim 17
Dependent Claim
20 words
The device of claim 11 wherein said metal is lead and said metal oxide is at least one lead oxide.
Claim 18
Dependent Claim
143 words
A superconducting device including: a thin superconducting film having a pair of substantially parallel major surfaces; and electrode means for applying an electric current to said film in a direction parallel to said surfaces; said device being formed by a process including the steps of; partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said chamber; and forming electrode means for applying current to said film in a direction parallel to said major surfaces; the partial pressure of said oxygen and said beam current being maintained at sufficient levels whereby; the current-voltage characteristic of said device is substantially indistinguishable from the current-voltage characteristic of a plurality of series connected Josephson tunnel junctions.
Claim 19
Dependent Claim
143 words
A superconducting device including: a thin superconducting film having a pair of substantially parallel major surfaces; and electrode means for applying an electric current to said film in a direction parallel to said surfaces; said device being formed by a process including the steps of; partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said chamber; and forming electrode means for applying current to said film in a direction parallel to said major surfaces; the partial pressure of said oxygen and said beam current being maintained at sufficient levels whereby; the current-voltage characteristic of said device is substantially indistinguishable from the current-voltage characteristic of a plurality of series connected Josephson tunnel junctions.
Claim 20
Dependent Claim
20 words
The superconducting device of claim 13 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 21
Dependent Claim
113 words
A superconducting device including: a superconducting thin film having a pair of substantially parallel spaced-apart major surfaces; and electrode means for applying an electric current to said film in a direction parallel to said surfaces; said film comprising: irregularly-shaped small metal grains having a plurality of orientations; and an insulating matrix, in which said grains are interspersed, comprising at least one oxide of said metal; said grains forming a cluster having an area essentially coextensive with said film; whereby said current, when having a value larger than a critical value, is capable of switching the voltage difference across said film in said direction from a first voltage difference to a second voltage difference.
Claim 22
Dependent Claim
113 words
A superconducting device including: a superconducting thin film having a pair of substantially parallel spaced-apart major surfaces; and electrode means for applying an electric current to said film in a direction parallel to said surfaces; said film comprising: irregularly-shaped small metal grains having a plurality of orientations; and an insulating matrix, in which said grains are interspersed, comprising at least one oxide of said metal; said grains forming a cluster having an area essentially coextensive with said film; whereby said current, when having a value larger than a critical value, is capable of switching the voltage difference across said film in said direction from a first voltage difference to a second voltage difference.
Claim 23
Dependent Claim
19 words
The device of claim 15 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 24
Dependent Claim
156 words
A superconducting device including: a thin superconducting film having a pair of substantially parallel spaced-apart major surfaces; and electrode means for applying an electric current to said film in a direction parallel to said surfaces; said device formed by a process including the steps of: partially evacuating an evacuable chamber; maintaining an atmosphere including oxygen therein; and directing a beam of ions at a metal target within said chamber thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said evacuable chamber; and forming electrode means for applying current to said film in a direction parallel to said surfaces; the partial pressure of said oxygen and said beam current being maintained at sufficient levels whereby; said current, when having a value larger than a critical value, is capable of switching the voltage difference across said film in said direction from a first voltage difference to a second voltage difference.
Claim 25
Dependent Claim
156 words
A superconducting device including: a thin superconducting film having a pair of substantially parallel spaced-apart major surfaces; and electrode means for applying an electric current to said film in a direction parallel to said surfaces; said device formed by a process including the steps of: partially evacuating an evacuable chamber; maintaining an atmosphere including oxygen therein; and directing a beam of ions at a metal target within said chamber thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said evacuable chamber; and forming electrode means for applying current to said film in a direction parallel to said surfaces; the partial pressure of said oxygen and said beam current being maintained at sufficient levels whereby; said current, when having a value larger than a critical value, is capable of switching the voltage difference across said film in said direction from a first voltage difference to a second voltage difference.
Claim 26
Dependent Claim
19 words
The device of claim 17 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 27
Dependent Claim
84 words
A process for forming a superconducting device, having a thin superconducting film, including the steps of: partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said chamber, whereby said film is hillock-resistant when subjected to thermal cycling; and forming electrode means coupled to said film for applying an electric current to said film.
Claim 28
Dependent Claim
84 words
A process for forming a superconducting device, having a thin superconducting film, including the steps of: partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said chamber, whereby said film is hillock-resistant when subjected to thermal cycling; and forming electrode means coupled to said film for applying an electric current to said film.
Claim 29
Dependent Claim
19 words
The process of claim 19 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 30
Dependent Claim
24 words
The process of claim 20 wherein said film has a normal state sheet resistance in the range of 10 Ω/square to 10 8 Ω/square.
Claim 31
Dependent Claim
65 words
The process of claim 20 wherein: said maintaining step includes maintaining the partial pressure of said oxygen in the approximate range of 10 -4 Torr to 10 -3 Torr; and said directing step includes directing a beam of ions at said target, said beam having a current density on the order of 0.5 mA/cm 2 and a voltage in the approximate range of 0.5-3 Kev.
Claim 32
Dependent Claim
122 words
A process for forming a superconducting device, having a thin superconducting film, including the steps of: partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said evacuable chamber; and forming electrode means for applying an electric current to said film in a direction parallel to a major surface of said film; the partial pressure of said oxygen and the ion beam current being maintained at sufficient levels whereby: the current-voltage characteristic of said device is substantially indistinguishable from the current voltage characteristic of a plurality of series connected Josephson tunnel junctions.
Claim 33
Dependent Claim
122 words
A process for forming a superconducting device, having a thin superconducting film, including the steps of: partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said evacuable chamber; and forming electrode means for applying an electric current to said film in a direction parallel to a major surface of said film; the partial pressure of said oxygen and the ion beam current being maintained at sufficient levels whereby: the current-voltage characteristic of said device is substantially indistinguishable from the current voltage characteristic of a plurality of series connected Josephson tunnel junctions.
Claim 34
Dependent Claim
19 words
The process of claim 23 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 35
Dependent Claim
24 words
The process of claim 24 wherein said film has a normal state sheet resistance in the approximate range of 500 Ω/square to 10,000 Ω/square.
Claim 36
Dependent Claim
40 words
The process of claim 24 wherein the partial pressure of oxygen is maintained in the approximate range of 5×10 -4 Torr to 10 -3 Torr and said ion beam current density is on the order of 0.5 mA/cm 2 .
Claim 37
Dependent Claim
133 words
A process for forming a superconducting device, having a thin superconducting film, including the steps of: partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said evacuable chamber; and forming electrode means for applying an electric current to said film in a direction parallel to a major surface of said film; the partial pressure of said oxygen and the ion beam current being maintained at sufficient levels whereby: said current, when having a value larger than a critical value, is capable of switching the voltage difference across said film in said direction from a first voltage difference to a second voltage difference.
Claim 38
Dependent Claim
133 words
A process for forming a superconducting device, having a thin superconducting film, including the steps of: partially evacuating an evacuable chamber; maintaining therein an atmosphere including oxygen; directing a beam of ions at a metal target within said chamber, thereby depositing said superconducting film comprising said metal and oxide of said metal on a substrate within said evacuable chamber; and forming electrode means for applying an electric current to said film in a direction parallel to a major surface of said film; the partial pressure of said oxygen and the ion beam current being maintained at sufficient levels whereby: said current, when having a value larger than a critical value, is capable of switching the voltage difference across said film in said direction from a first voltage difference to a second voltage difference.
Claim 39
Dependent Claim
19 words
The process of claim 27 wherein said metal is lead and said oxide is at least one lead oxide.
Claim 40
Dependent Claim
24 words
The process of claim 28 wherein said film has a normal state sheet resistance in the approximate range of 10 Ω/square to 500 Ω/square.
Claim 41
Dependent Claim
40 words
The process of claim 28 wherein the partial pressure of oxygen is maintained in the approximate range of 1×10 -4 Torr to 5×10 -4 Torr and said ion beam current density is on the order of 0.5 mA/cm 2 .
References Cited (Backward Citations)
GB1244011A
Cited
US4012756A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-08 | 1986-05-10 | 1986-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-08 | 1990-05-10 | 1990-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-08 | 1994-05-10 | 1994-11-09 | $7700.00 | Window Closed / Lapsed |