US4844989A
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Superconducting structure with layers of niobium nitride and aluminum nitride
Assignee: United States Department of Energy
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Filing: 1987-03-19
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Granted: 1989-07-04
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Expires: 2007-03-19
Abstract
Abstract A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources.
Inventors
- 👤 James M. Murduck
- 👤 Yves J. Lepetre
- 👤 Ivan K. Schuller
- 👤 John B. Ketterson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:12
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/80; H10N60/85; H10N60/855; H10N60/10; H10N60/12
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
48 words
A multi-layered structure adapted for operating as a superconductor at high critical current densities comprising, alternating layers of niobium nitride and aluminum nitride having thicknesses of the order of 20 to 200 Angstroms, and the number of layers of each being in the range of 10 to 1000.
Claim 2
Dependent Claim
48 words
A multi-layered structure adapted for operating as a superconductor at high critical current densities comprising, alternating layers of niobium nitride and aluminum nitride having thicknesses of the order of 20 to 200 Angstroms, and the number of layers of each being in the range of 10 to 1000.
Claim 3
Dependent Claim
17 words
The structure of claim 1 comprising in addition a substrate upon which the multi-layered structure is disposed.
Claim 4
Dependent Claim
35 words
The structure of claim 1 wherein the aluminum nitride is deposited in the (0001) wurtzite crystal structure and wherein the niobium nitride is disposed in the sodium chloride cubical crystal structure in a (111) orientation.
Claim 5
Dependent Claim
37 words
The structure of claim 3 wherein the layers of aluminum nitride are each of the order 20 Angstroms in thickness, and wherein the layers of niobium nitride are each of the order of 70 Angstroms in thickness.
Claim 6
Dependent Claim
17 words
The structure of claim 3 comprising in addition a substrate upon which the multi-layered structure is disposed.
Claim 7
Dependent Claim
10 words
The structure of claim 5 wherein the substrate is sapphire.
Claim 8
Dependent Claim
23 words
The structure of claim 5 wherein the substrate is made of a metal selected from the group consisting of copper, steel, or hastelloy.
Claim 9
Dependent Claim
61 words
A three-layered superconductor structure having an enhanced critical temperature comprising, a layer of niobium nitride deposited on a substrate, a second layer of aluminum nitride deposited on the first layer, and a third layer of niobium nitride deposited on the second layer, the three-layered structure forming a Josephson junction when cooled to temperatures at which the niobium nitride is a superconductor.
Claim 10
Dependent Claim
61 words
A three-layered superconductor structure having an enhanced critical temperature comprising, a layer of niobium nitride deposited on a substrate, a second layer of aluminum nitride deposited on the first layer, and a third layer of niobium nitride deposited on the second layer, the three-layered structure forming a Josephson junction when cooled to temperatures at which the niobium nitride is a superconductor.
Claim 11
Dependent Claim
29 words
The structure of claim 8 wherein the aluminum nitride is between 5 and 200 Angstroms in thickness and wherein the niobium nitride is greater than 20 Angstroms in thickness.
Claim 12
Dependent Claim
24 words
A multi-layered structure adapted for operating as a superconductor at high critical current densities comprising, alternating thin layers of niobium nitride and aluminum nitride.
Claim 13
Dependent Claim
24 words
A multi-layered structure adapted for operating as a superconductor at high critical current densities comprising, alternating thin layers of niobium nitride and aluminum nitride.
Claim 14
Dependent Claim
23 words
The multi-layered structure as defined in claim 10 wherein said alternating thin layers comprise layer thicknesses of the order of about 20-350 Angstroms.
Claim 15
Dependent Claim
44 words
A multi-layered structure adapted for operating as a superconductor at high critical current densities comprising, alternating thin layers of niobium nitride and an insulating material structurally compatible with said niobium nitride layer, thereby securely bonding said niobium nitride layer to said insulating material layer.
Claim 16
Dependent Claim
44 words
A multi-layered structure adapted for operating as a superconductor at high critical current densities comprising, alternating thin layers of niobium nitride and an insulating material structurally compatible with said niobium nitride layer, thereby securely bonding said niobium nitride layer to said insulating material layer.
Claim 17
Dependent Claim
46 words
A superconductor having a multi-layered structure comprising, alternating thin layers of niobium nitride and aluminum nitride, the number of said alternating layers being in excess of 10, said superconductor adapted to function with at least one of high critical current density and enhanced parallel critical fields.
Claim 18
Dependent Claim
46 words
A superconductor having a multi-layered structure comprising, alternating thin layers of niobium nitride and aluminum nitride, the number of said alternating layers being in excess of 10, said superconductor adapted to function with at least one of high critical current density and enhanced parallel critical fields.
Claim 19
Dependent Claim
23 words
A voltage controlled microwave energy source comprising, a superconductor having a multi-layered structure including alternating thin layers of niobium nitride and aluminum nitride.
Claim 20
Dependent Claim
23 words
A voltage controlled microwave energy source comprising, a superconductor having a multi-layered structure including alternating thin layers of niobium nitride and aluminum nitride.
Claim 21
Dependent Claim
24 words
A multi-layered structure adapted for operating as a superconductor with enhanced parallel critical fields, comprising alternating thin layers of niobium nitride and aluminum nitride.
Claim 22
Dependent Claim
24 words
A multi-layered structure adapted for operating as a superconductor with enhanced parallel critical fields, comprising alternating thin layers of niobium nitride and aluminum nitride.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-03 | 1993-01-02 | 1993-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-03 | 1997-01-02 | 1997-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-03 | 2001-01-02 | 2001-07-04 | $7700.00 | Window Closed / Lapsed |