EP0478466A1
Expired / Lapsed
EP
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A superconducting device and a method for manufacturing the same
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1991-09-27
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Granted: —
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Expires: 2011-09-27
Abstract
Abstract In a superconducting device or a super-FET having a pair of superconducting electrode regions (20b, 20c) consisting of a thin film (20) oxide superconductor being deposited on a substrate (5) and a weak link region (20a), the superconducting electrode regions (20b, 20c) being positioned at opposite sides of the weak link region (20a), these superconducting electrode regions (20b, 20c) and the weak link region (20a) being formed on a common plane surface of the substrate (5), improvement in that the weak link region (20a) is produced by local diffusion of consistent element(s) of the substrate (5) into the thin film (20) of oxide superconductor in such a manner that a substantial wall thickness of the thin film (20) of oxide superconductor is reduced at the weak link region (20a) so as to leave a weak link or superconducting channel (10) in the thin film (20) of oxide superconductor over a non-superconducting region (50) which is produced by the diffusion.
Inventors
- 👤 Takao Nakamura
- 👤 Hiroshi Inada
- 👤 Michitomo Iiyama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 11:35
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/20; H10N60/205; H10N60/207; H10N60/01; H10N60/0912; H10N60/0941; H10N60/10; H10N60/12; H10N60/124; Y; Y10; Y10S; Y10S505/00; Y10S505/70; Y10S505/701; Y10S505/702
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
169 words
A superconducting device having a pair of superconducting electrode regions consisting of a thin film of oxide superconductor having a sufficiently thick wall-thickness and being deposited on a substrate and a weak link region, said superconducting electrode regions being positioned at opposite sides of said weak link region, both of said superconducting electrode regions and said weak link region being formed on a common plane surface of said substrate, characterized in that said weak link region is produced by diffusing a consistent element or elements of which said substrate is made into said thin film of oxide superconductor deposited on said substrate at a potion of said thin film of oxide superconductor which corresponds to said weak link region in such a manner that a substantial wall thickness of said thin film of oxide superconductor is reduced at said weak link region so as to leave a weak link or superconducting channel in said thin film of oxide superconductor over a non-superconducting region which is produced by the diffusion.
Claim 2
Dependent Claim
62 words
The superconducting device set forth in claim 1 wherein a source electrode and a drain electrode for supplying a superconducting current passing through said superconducting channel are deposited on said thin film of oxide superconductor on respective superconducting electrode regions at opposite sides of said superconducting channel, and a gate electrode for controlling said superconducting current is positioned over said superconducting channel.
Claim 3
Dependent Claim
54 words
The superconducting device set forth in claim 1 or 2 wherein said non-superconducting region being produced by diffusion of a dopant which can diffuse easily into said thin film of oxide superconductor and destroy the superconductivity of said oxide superconductor and which is added onto a surface of said thin film of oxide superconductor.
Claim 4
Dependent Claim
37 words
The superconducting device set forth in any one of claim 1 to 3 wherein said non-superconducting region is formed by a reaction between an element or elements of which said substrate is made and said oxide superconductor.
Claim 5
Dependent Claim
48 words
The superconducting device set forth in any one of claim 1 to 4 wherein said non-superconducting region is formed by diffusion of an element or elements of which said substrate caused by irradiating a predetermined limited portion of said thin film of oxide superconductor with an energy beam
Claim 6
Dependent Claim
16 words
The superconducting device set forth in claim 5 wherein said energy beam is a laser beam.
Claim 7
Dependent Claim
17 words
The superconducting device set forth in claim 5 wherein said energy beam is a focussed ion beam.
Claim 8
Dependent Claim
28 words
The superconducting device set forth in any one of claim 2 to 5 wherein an insulating layer is further interposed between said gate electrode and said superconducting channel.
Claim 9
Dependent Claim
36 words
The superconducting device set forth in claim 8 wherein another non-superconducting region is formed between said insulating layer and said superconducting channel by diffusion of an element or elements of which said insulating layer is made.
Claim 10
Dependent Claim
22 words
The superconducting device set forth in claim 9 wherein said diffusion of element(s) of said insulating layer is effected by Joule heat.
Claim 11
Independent Claim
155 words
A method for manufacturing a superconducting device having a pair of superconducting electrode regions consisting of a thin film oxide superconductor having a sufficiently thick wall-thickness and being deposited on a substrate and a weak link region, said superconducting electrode regions being positioned at opposite sides of said weak link region, both of said superconducting electrode regions and said weak link region being formed on a common plane surface of said substrate, characterized by the steps of depositing a thin film of oxide superconductor having a thickness which is sufficient to provide said superconducting electrode regions on said substrate, and diffusing a constituent element or elements of which said substrate is made into said thin film of oxide superconductor to produce a non-superconducting region in said thin film of oxide superconductor in such a manner that a weak link or superconducting channel is left in said thin film of oxide superconductor over said non-superconducting region.
Claim 12
Dependent Claim
57 words
The method set forth in claim 11, wherein the diffusion of constituent element or elements of which said substrate is made into said thin film of oxide superconductor is effected by heat-treatment or irradiation of an energy beam which is directed onto a portion of said thin film of oxide superconductor which corresponds to said weak link.
Claim 13
Dependent Claim
15 words
The method set forth in claim 12 wherein said energy beam is a laser beam.
Claim 14
Dependent Claim
16 words
The method set forth in claim 12 wherein said energy beam is a focussed ion beam.
Claim 15
Dependent Claim
14 words
The method set forth in claim 12 wherein said energy beam is light beam.
Claim 16
Dependent Claim
15 words
The method set forth in claim 12 wherein said heat-treatment is effected with Joule heat.
Claim 17
Dependent Claim
80 words
The method set forth in any one of claim 11 to 16 wherein the method includes further the steps of doping locally a portion of said substrate with an dopant which can diffuse easily into said thin film of oxide superconductor and destroy the superconductivity of said oxide superconductor before said thin film of oxide superconductor is deposited on said substrate and then diffusing said dopant into said thin film of oxide superconductor so as to form said non-superconducting region.
Claim 18
Dependent Claim
71 words
The method set forth in any one of claim 11 to 17 wherein the method includes further the steps of forming a source electrode and a drain electrode for supplying a superconducting current passing through said superconducting channel on said thin film of oxide superconductor on respective superconducting electrode regions at opposite sides of said superconducting channel, and forming a gate electrode for controlling said superconducting current over said superconducting channel.
Claim 19
Dependent Claim
75 words
The method set forth in any one of claim 11 to 18 wherein the method includes further the steps of forming a reflective film on said thin film of oxide superconductor, said reflective film having an opening at a position corresponding to said weak link region, and then subjecting said reflective film to lamp-annealing from a side of said reflective film so as to develop diffusion of the constituent element or elements of said substrate.
Claim 20
Dependent Claim
130 words
The method set forth in claim 11 wherein the method includes further the steps of depositing successively an insulating layer and an ordinary conducting layer on said thin film of oxide superconductor, forming a gate insulating layer and a gate electrode by patterning of said insulating layer and said ordinary conducting layer, applying an electric current to said gate electrode to heat locally said thin film of oxide superconductor so that an element or elements of which said substrate and/or said gate insulating layer is made diffuse into said thin film of oxide superconductor at the heated region, so that at least one non-superconducting region is formed between said insulating layer and said superconducting channel and/or between said substrate and said superconducting channel which is delimited by said non-superconducting regions.
References Cited (Backward Citations)
EP0276746A2
Cited
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