EP0484253A2
Expired / Lapsed
EP
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Superconducting device having an extremely thin superconducting channel formed of oxide superconductor material and method for manufacturing the same
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1991-11-04
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Granted: —
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Expires: 2011-11-04
Abstract
Abstract A superconducting device comprises a substrate, an extremely thin superconducting channel formed of an oxide superconductor on the principal surface of said substrate. A superconducting source electrode and a superconducting drain electrode of a relatively thick thickness is formed of the oxide superconductor on said superconducting channel separated from each other but electrically connected by said superconducting channel, so that a superconducting current can flow through said superconducting channel between the superconducting source electrode and the superconducting drain electrode. A superconducting gate electrode is formed of the oxide superconductor through a gate insulator on said superconducting channel for controlling the superconducting current flowing through said superconducting channel. And a side insulating region is formed to completely cover each of opposite side surfaces of the superconducting gate electrode. The superconducting channel and the gate insulator are formed of the same oxide thin film of which oxygen amount is locally decreased and said gate insulator being formed of a compound oxide which is composed of the same constituent elements as those of the oxide superconductor of which the superconducting channel is formed but includes the oxygen amount less than that of said oxide superconductor. And the superconducting gate electrode is surrounded by the superconducting channel, the superconducting source electrode and the superconducting drain electrode but electrically isolated from the superconducting channel, the superconducting source electrode and the superconducting drain electrode by the gate insulator and the side insulating region.
Inventors
- 👤 Hiroshi Inada
- 👤 Takao Nakamura
- 👤 Michitomo Iiyama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 21:32
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/20; H10N60/205; H10N60/207; Y; Y10; Y10S; Y10S505/00; Y10S505/70; Y10S505/701; Y10S505/702; Y10S505/725; Y10S505/729
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
234 words
A superconducting device comprising a substrate, an extremely thin superconducting channel formed of an oxide superconductor on the principal surface of said substrate, a superconducting source electrode and a superconducting drain electrode of a relatively thick thickness formed of the oxide superconductor on said superconducting channel separated from each other but electrically connected by said superconducting channel, so that a superconducting current can flow through said superconducting channel between the superconducting source electrode and the superconducting drain electrode, a superconducting gate electrode formed of the oxide superconductor through a gate insulator on said superconducting channel for controlling the superconducting current flowing through said superconducting channel, and a side insulating region formed to completely cover each of opposite side surfaces of the superconducting gate electrode, the superconducting channel and the gate insulator being formed of the same oxide thin film of which oxygen amount is locally decreased and said gate insulator being formed of a compound oxide which is composed of the same constituent elements as those of the oxide superconductor of which the superconducting channel is formed but includes the oxygen amount less than that of said oxide superconductor, and the superconducting gate electrode being surrounded by the superconducting channel, the superconducting source electrode and the superconducting drain electrode but electrically isolated from the superconducting channel, the superconducting source electrode and the superconducting drain electrode by the gate insulator and the side insulating region.
Claim 2
Dependent Claim
42 words
A superconducting device claimed in Claim 1 wherein the superconducting channel is formed of a c -axis orientated oxide superconductor thin film and the superconducting source electrode and the superconducting drain electrode is formed of a -axis orientated oxide superconductor thin films.
Claim 3
Dependent Claim
32 words
A superconducting device claimed in Claim 1 wherein the oxide superconductor is formed of high-T c (high critical temperature) oxide superconductor, particularly, formed of a high-T c copper-oxide type compound oxide superconductor.
Claim 4
Dependent Claim
45 words
A superconducting device claimed in Claim 3 wherein the oxide superconductor is formed of oxide superconductor material selected from the group consisting of a Y-Ba-Cu-O type compound oxide superconductor material, a Bi-Sr-Ca-Cu-O type compound oxide superconductor material, and a Tl-Ba-Ca-Cu-O type compound oxide superconductor material.
Claim 5
Dependent Claim
33 words
A superconducting device claimed in Claim 1 further including a surface protector formed on an upper surface of the superconducting gate electrode, which covers the upper surface of the superconducting gate electrode completely.
Claim 6
Dependent Claim
21 words
A superconducting device claimed in Claim 5 wherein the surface protector is formed of a metal material or an insulating material.
Claim 7
Dependent Claim
35 words
A superconducting device claimed in Claim 5 wherein the surface protector is formed of a stacked structure including a photo resist layer and a metal layer, or a photo resist layer and an insulating layer.
Claim 8
Dependent Claim
82 words
A superconducting device claimed in Claim 1 wherein the superconducting channel, the gate insulator and the superconducting gate electrode are formed of the same oxide thin film of which oxygen amount is locally decreased and said gate insulator being formed of a compound oxide which is composed of the same constituent elements as those of the oxide superconductor of which the superconducting channel and the superconducting gate electrode are formed but includes the oxygen amount less than that of said oxide superconductor.
Claim 9
Dependent Claim
27 words
A superconducting device claimed in Claim 8 wherein the superconducting channel and the superconducting gate electrode are formed of a c -axis orientated oxide superconductor thin film.
Claim 10
Dependent Claim
23 words
A superconducting device claimed in Claim 2 wherein the superconducting gate electrode are formed of an a -axis orientated oxide superconductor thin film.
Claim 11
Dependent Claim
17 words
A superconducting device claimed in Claim 1 wherein the side insulating region includes an oxygen barrier layer.
Claim 12
Dependent Claim
17 words
A superconducting device claimed in Claim 11 wherein the oxygen barrier layer is formed of silicon nitride.
Claim 13
Dependent Claim
21 words
A superconducting device claimed in Claim 11 wherein the side insulating region includes another insulator layer than said oxygen barrier layer.
Claim 14
Dependent Claim
15 words
A superconducting device claimed in Claim 13 wherein the insulator layer is formed of MgO.
Claim 15
Dependent Claim
38 words
A superconducting device claimed in Claim 1 wherein the substrate is formed of a material selected from the group consisting of a MgO (100) substrate, a SrTiO₃ (100) substrate and a CdNdAlO₄ (001) substrate, and a semiconductor substrate.
Claim 16
Dependent Claim
42 words
A superconducting device claimed in Claim 1 wherein the substrate is formed of a silicon substrate and a principal surface of the silicon substrate is coated with an insulating material layer which is formed of a MgAlO₄ layer and a BaTiO₃ layer.
Claim 17
Independent Claim
204 words
A method of manufacturing a superconducting device, comprising the steps of forming on a surface of a substrate a first oxide superconductor thin film, forming a superconducting gate electrode of the oxide superconductor on a portion of said oxide superconductor thin film, etching portions of said oxide superconductor thin film at the both sides of the superconducting gate electrode using the superconducting gate electrode as a mask, so that a superconducting channel of an extremely thin oxide superconductor thin film is formed under the superconducting gate electrode and a step portion is formed on an upper surface of the superconducting channel and under the superconducting gate electrode, heating the substrate under high vacuum so that oxygen of the oxide superconductor of the step portion escapes and the oxide superconductor of the step portion is converted into an oxide insulating material and the step portion changes to a gate insulator, and growing a second oxide superconductor thin film on the exposed surface of the superconducting channel, using the gate electrode as a mask, so that a superconducting source electrode and a superconducting drain electrode having a relatively thick thickness are formed at opposite sides of the superconducting gate electrode, electrically isolated from the gate electrode.
Claim 18
Dependent Claim
38 words
A method claimed in Claim 17 wherein the first oxide superconductor thin film is a c -axis orientated oxide superconductor thin film and the second oxide superconductor thin film is an a -axis orientated oxide superconductor thin film.
Claim 19
Dependent Claim
36 words
A method claimed in Claim 18 wherein the superconducting gate electrode, the gate insulator and the superconducting channel are formed of the same oxide thin film which is prepared from the first oxide superconductor thin film.
Claim 20
Dependent Claim
94 words
A method claimed in Claim 17 further comprising the steps of depositing an a -axis orientated oxide superconductor thin film on the first oxide superconductor thin film for a superconducting gate electrode, forming a surface protector on a portion of said superconducting gate electrode, and etching portions of said a -axis orientated oxide superconductor thin film at the both side of the surface protector so as to remove all of the a -axis orientated oxide superconductor thin film excluding a portion which becomes the superconducting gate electrode using the surface protector as a mask.
References Cited (Backward Citations)
No citation records indexed.
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