EP0359411A2
Expired / Lapsed
EP
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High-frequency substrate material for thin-film layered perovskite superconductors
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1989-08-17
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Granted: —
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Expires: 2009-08-17
Abstract
Abstract A lanthanum aluminate (LaAlO₃) substrate on which thin films of layered perovskite copper oxide superconductors are formed. Lanthanum aluminate, with a pseudo-cubic perovskite crystal structure, has a crystal structure and lattice constant that closely match the crystal structures and lattice constants of the layered perovskite superconductors. Therefore, it promotes epitaxial film growth of the superconductors, with the crystals being oriented in the proper direction for good superconductive electrical properties, such as a high critical current density. In addition, LaAlO₃ has good high frequency properties, such as a low loss tangent and low dielectric constant at superconductive temperatures. Finally, lanthanum aluminate does not significantly interact with the superconductors. Lanthanum aluminate can also used to form thin insulating films between the superconductor layers, which allows for the fabrication of a wide variety of superconductor circuit elements.
Inventors
- 👤 Randy Wayne Simon
- 👤 Christine Elizabeth Platt
- 👤 Alfred Euinam Lee
- 👤 Gregory Steven Lee
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 03:36
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/10; H10N60/12; H10N60/124; H01; H01P; H01P11/00; H01P11/001; H01P11/003; H01P3/00; H01P3/003; H01P3/02; H01P3/08; H01P3/081; H10N60/01; H10N60/0268; H10N60/0296; H10N60/0576; H10N60/0604; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/93; Y10S505/00; Y10S505/70; Y10S505/701; Y10S505/702; Y10S505/703; Y10S505/704; Y10S505/825; Y10S505/856; Y10S505/866; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24926
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
20 words
A substrate for deposition of thin films of layered perovskite copper oxide superconductors, comprising: a wafer of lanthanum aluminate (LaAlO₃).
Claim 2
Dependent Claim
20 words
A substrate for deposition of thin films of layered perovskite copper oxide superconductors, comprising: a wafer of lanthanum aluminate (LaAlO₃).
Claim 3
Independent Claim
30 words
A method for forming thin films of layered perovskite copper oxide superconductors on a substrate, comprising the step of: depositing the superconductor films on a substrate of lanthanum aluminate (LaAlO₃).
Claim 4
Independent Claim
30 words
A method for forming thin films of layered perovskite copper oxide superconductors on a substrate, comprising the step of: depositing the superconductor films on a substrate of lanthanum aluminate (LaAlO₃).
Claim 5
Dependent Claim
27 words
A superconductive microwave circuit element, comprising: a lanthanum aluminate (LaAlO₃) substrate; and one or more thin films of a layered perovskite superconductor deposited on the LaAlO₃ substrate.
Claim 6
Dependent Claim
27 words
A superconductive microwave circuit element, comprising: a lanthanum aluminate (LaAlO₃) substrate; and one or more thin films of a layered perovskite superconductor deposited on the LaAlO₃ substrate.
Claim 7
Dependent Claim
80 words
The superconductive microwave circuit element as set forth in claim 3, wherein the thin superconductor films include: a first thin film of the layered perovskite superconductor deposited on the substrate; a thin insulating film of LaAlO₃ deposited on the first superconductor film; and a second thin film of the layered perovskite superconductor deposited on the insulating film; wherein the two superconductor films are the electrodes of a Josephson junction and the insulating film is the barrier through which tunneling occurs.
Claim 8
Dependent Claim
76 words
The superconductive microwave circuit element as set forth in claim 3, wherein the thin superconductor films include: a narrow thin film of the layered perovskite superconductor deposited on the substrate; and two wide thin films of the layered perovskite superconductor deposited on the substrate on either side of the narrow superconductor film; wherein the narrow superconductor film is the conductor of a coplanar waveguide and the two wide superconductor films are the walls of the waveguide.
Claim 9
Dependent Claim
83 words
The superconductive microwave circuit element as set forth in claim 3, wherein the thin superconductor films include: a thin film of the layered perovskite superconductor deposited on the substrate; a thin insulating film of LaAlO₃ deposited on the superconductor film; and a narrow thin film of the layered perovskite superconductor deposited on the insulating film; wherein the thin superconductor film is the ground plane of a microstrip transmission line, the insulating film is the dielectric and the narrow superconductor film is the conductor.
Claim 10
Independent Claim
35 words
A method for fabricating a superconductive microwave circuit element, comprising the steps of: forming a lanthanum aluminate (LaAlO₃) substrate; and depositing one or more thin films of a layered perovskite superconductor on the LaAlO₃ substrate.
Claim 11
Independent Claim
35 words
A method for fabricating a superconductive microwave circuit element, comprising the steps of: forming a lanthanum aluminate (LaAlO₃) substrate; and depositing one or more thin films of a layered perovskite superconductor on the LaAlO₃ substrate.
Claim 12
Dependent Claim
87 words
The method for fabricating a superconductive microwave circuit element as set forth in claim 7, wherein the step of depositing includes the steps of: depositing a first thin film of the layered perovskite superconductor on the substrate; depositing a thin insulating film of LaAlO₃ on the first superconductor film; and depositing a second thin film of the layered perovskite superconductor on the insulating film; wherein the two superconductor films are the electrodes of a Josephson junction and the insulating film is the barrier through which tunneling occurs.
Claim 13
Dependent Claim
83 words
The method for fabricating a superconductive microwave circuit element as set forth in claim 7, wherein the step of depositing includes the steps of: depositing a narrow thin film of the layered perovskite superconductor on the substrate; and depositing two wide thin films of the layered perovskite superconductor on the substrate on either side of the narrow superconductor film; wherein the narrow superconductor film is the conductor of a coplanar waveguide and the two wide superconductor films are the walls of the waveguide.
Claim 14
Dependent Claim
90 words
The method for fabricating a superconductive microwave circuit element as set forth in claim 7, wherein the step of depositing includes the steps of: depositing a thin film of the layered perovskite superconductor on the substrate; depositing a thin insulating film of LaAlO₃ on the superconductor film; and depositing a narrow thin film of the layered perovskite superconductor on the insulating film; wherein the thin superconductor film is the ground plane of a microstrip transmission line, the insulating film is the dielectric and the narrow superconductor film is the conductor.
References Cited (Backward Citations)
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