US3816173A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fabrication of variable current density josephson junctions
Assignee: International Business Machines Corp
•
Filing: 1972-11-29
•
Granted: 1974-06-11
•
Expires: 1992-11-29
Abstract
Abstract Alloying the base electrode of a lead-oxide-lead Josephson tunnel junction with indium will effectively result in an oxide having a low barrier height. Consequently, much thicker barriers can be produced without severely limiting the magnitude of the tunnel current. Furthermore, by varying the indium concentration in an array of Pb-In electrodes on a single chip, one can produce various different functioning devices while employing only a single oxidation process.
Inventors
- 👤 J Eldridge
- 👤 J Matisoo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:20
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/01; H10N60/0912; H10N60/10; H10N60/12; Y; Y10; Y10S; Y10S505/00; Y10S505/80; Y10S505/815; Y10S505/818
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
112 words
In a method for controlling the height of the tunnel barrier, and therefore its maximum tunneling current, for a given oxide thickness of a Josephson junction comprising the steps of a. providing an alloyed electrode of lead and tellurium, wherein said tellurium varies from 1 to 20% by weight of the Pb-Te alloy, b. oxidizing said alloy to produce an oxide consisting of lead oxide and tellurium oxide on the surface of said electrode, and c. selecting the ratio of Pb to Te in said alloyed electrode so as to obtain a desired lead oxide to tellurium oxide ratio, said ratio fixing the tunnel barrier height for said given thickness of oxide.
Claim 2
Dependent Claim
112 words
In a method for controlling the height of the tunnel barrier, and therefore its maximum tunneling current, for a given oxide thickness of a Josephson junction comprising the steps of a. providing an alloyed electrode of lead and tin, wherein said tin varies from 1 to 20% by weight of the Pb-Sn alloy, b. oxidizing said alloy to produce an oxide consisting of lead oxide and tin oxide on the surface of said electrode, and c. selecting the ratio of Pb to Sn in said alloyed electrode so as to obtain a desired lead oxide to tin oxide ratio, said ratio fixing the tunnel barrier height for said given thickness of oxide.
Claim 3
Dependent Claim
111 words
In a method for controlling the height of the tunnel barrier, and therefore its maximum tunneling current, for a given oxide thickness of a Josephson junction comprising the steps of a. providing an alloyed electrode of lead and bismuth said bismuth varies from 1 to 20% by weight of the Pb-Bi alloy, b. oxidizing said alloy to produce an oxide consisting of lead oxide and bismuth oxide on the surface of said electrode, and c. selecting the ratio of Pb to Bi in said alloyed electrode so as to obtain a desired lead oxide to bismuth oxide ratio, said ratio fixing the tunnel barrier height for said given thickness of oxide.
Claim 4
Dependent Claim
107 words
In a method for controlling the height of the tunnel barrier, and therefore its maximum tunneling current, for a given oxide thickness of a Josephson junction comprising the steps of a. providing an alloyed electrode of lead and a metal having a valence greater than 2, b. oxidizing said alloy to produce an oxide consisting of PbO and the oxide of metal on the surface of said electrode, and c. selecting the ratio of Pb to said metal in said alloyed electrode so as to obtain a desired lead oxide to metal oxide ratio, said ratio fixing the tunnel barrier height for said given thickness of oxide.
Claim 5
Dependent Claim
106 words
In a method for making an array of Josephson junction devices on a single chip comprising the steps of a. providing a plurality of discrete superconductive electrodes on an insulated substrate, b. incorporating different amounts of indium in selected groups of electrodes in said array, c. oxidizing said electrodes so as to obtain a different metal oxide-indium-oxide ratio for each group in said array, and d. depositing a second superconductive electrode on each oxidized layer in said array whereby an array of Josephson junctions is produced wherein each group has different critical currents than any of the other groups even though oxidized at the same time.
Claim 6
Dependent Claim
113 words
In a method for making an array of Josephson junction devices on a single chip comprising the steps of a. providing a plurality of discrete superconductive electrodes on an insulated substrate; b. incorporating different amounts of a metal having a valence grEater than 2 in selected groups of electrodes in said array; c. oxidizing said electrodes so as to obtain a different electrode oxide-metal oxide ratio for each group in said array; and d. depositing a second superconductive electrode on each member of each group whereby an array of Josephson junctions is produced wherein each group has different critical currents than any of the other groups even though oxidized at the same time.
References Cited (Backward Citations)
US3394317A
Cited
US3733526A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |