Patent US4536781A successfully refreshed from Google Patents.
US4536781A
Expired / Lapsed
US
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Fabrication of superconductive tunneling junction resistors and short circuits by ion implantation
Assignee: Unisys Corp
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Filing: 1983-02-22
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Granted: 1985-08-20
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Expires: 2003-02-22
Abstract
Abstract A superconductive junction device for fabricating Josephson integrated circuits is useful for replacing deposited thin-film resistors and for short-circuit device interconnections. Derived by "poisoning" a superconductive electrode or altering the barrier of a tunnel junction, the device displays controllable resistive properties at normal superconducting transition temperatures at substantial savings in the space occupied. Methods of fabricating the device using the selective niobium anodization process and ion implantation process are disclosed. When both upper and lower superconductive electrodes are poisoned, the device has linear properties whose resistance is identical to the normal resistance of unpoisoned junctions. Superconducting short circuits are readily obtained by oxygen ion implantation in thin film niobium electrodes.
Inventors
- 👤 Harry Kroger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:34
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/01; H10N60/0912; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/873; Y10S505/874
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
84 words
In a junction device including: a first layer of superconductive material, characterized by a superconducting transition temperature; a second layer of conductive material, superposed with respect to said first layer; a barrier layer between said first and second layers for conducting tunneling current therebetween; and means for providing at least one limited region wherein said junction device has a predetermined ohmic resistance when cooled to said superconducting transition temperature; said means comprising: chemical impurities implanted into at least a portion of said barrier layer.
Claim 2
Dependent Claim
84 words
In a junction device including: a first layer of superconductive material, characterized by a superconducting transition temperature; a second layer of conductive material, superposed with respect to said first layer; a barrier layer between said first and second layers for conducting tunneling current therebetween; and means for providing at least one limited region wherein said junction device has a predetermined ohmic resistance when cooled to said superconducting transition temperature; said means comprising: chemical impurities implanted into at least a portion of said barrier layer.
Claim 3
Dependent Claim
18 words
A junction device as set forth in claim 1, wherein said chemical impurities are added by ion implantation.
Claim 4
Dependent Claim
15 words
A junction device as set forth in claim 1 comprised of superconductor-insulator-normal layers of material.
Claim 5
Dependent Claim
19 words
A junction device as set forth in claim 3, wherein said predetermined ohmic resistance varies non-linearly with applied voltage.
Claim 6
Dependent Claim
12 words
A junction device as set forth in claim 1 comprising normal-insulator-normal materials.
Claim 7
Dependent Claim
22 words
A junction device as set forth in claim 5 wherein said predetermined ohmic resistance is constant over a range of applied voltage.
Claim 8
Dependent Claim
25 words
A junction device as set forth in claim 1 wherein said predetermined ohmic resistance is characterized by the normal resistance of an associated superconductor-insulator-superconductor junction.
Claim 9
Dependent Claim
31 words
The junction device as described in claim 1 wherein at least one of said first and second layers of materials is selected from the group consisting of niobium and niobium nitride.
Claim 10
Dependent Claim
42 words
A junction device as set forth in claim 2 wherein said chemical impurities consist of a gas selected from the group consisting of oxygen and hydrogen, and at least one of said first and second layers of material is comprised of niobium.
Claim 11
Dependent Claim
49 words
A junction device as set forth in claim 9, wherein said chemical impurities include oxygen ions of density ranging from 1×10 4 to 1×10 16 O 16 + /cm 2 , and said ions are accelerated by an applied energy level of 25×10 3 to 65×10 3 electron volts.
Claim 12
Dependent Claim
46 words
A junction device as set forth in claim 2 wherein said chemical impurities are implanted to a predetermined depth including the sum of the thicknesses of at least one of said first and second layer of material and at least a portion of said barrier layer.
Claim 13
Dependent Claim
43 words
A junction device as set forth in claim 2 wherein said chemical impurities are implanted to a predetermined depth including the sum of the thicknesses of said first layer and said barrier, and at least a portion of said second layer of material.
Claim 14
Dependent Claim
15 words
A junction device as set forth in claim 1, comprised of superconductor-insulator-superconductor layers of material.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-08-19 | 1989-02-18 | 1989-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-19 | 1993-02-18 | 1993-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-19 | 1997-02-18 | 1997-08-20 | $7700.00 | Window Closed / Lapsed |