US4279969A
Expired / Lapsed
US
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Method of forming thin niobium carbonitride superconducting films of exceptional purity
Assignee: United States Department of the Navy
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Filing: 1980-02-20
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Granted: 1981-07-21
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Expires: 2000-02-20
Abstract
Abstract Thin superconducting NbCN films are deposited by reactive sputtering onto a dielectric substrate inside a vacuum chamber. The substrate is heated to a temperature of 600°-1200° C., ultra-pure Argon is introduced into the chamber, and niobium is presputtered from a high-purity target onto a shutter. A cyanogen and nitrogen gas mixture is introduced into the chamber at a rate of approximately 10 -6 Torr liters/sec, and a shutter is opened exposing the substrate to the sputtered niobium. The deposited niobium reacts with the cyanogen-nitrogen gas mixture to form NbCN films of exceptional purity, and which exhibit superior superconductor properties.
Inventors
- 👤 Thomas L. Francavilla
- 👤 Stuart A. Wolf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:52
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/06; C23C14/0664; H; H10; H10N; H10N60/00; H10N60/01; H10N60/0241; H10N60/80; H10N60/85; Y; Y10; Y10S; Y10S505/00; Y10S505/80; Y10S505/812; Y10S505/813; Y10S505/815; Y10S505/816
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
221 words
A method for the preparation of superconducting thin films of niobium carbonitride of exceptional purity, comprising: assembling within a closed reactor a dielectric substrate and a pure niobium target; evacuating the reactor to a pressure of about 10 -10 Torr, while heating the components contained within the reactor so as to substantially eliminate all volatile impurities therefrom; admitting an inert gas into the reactor until the inert gas attains a pressure within the range of about 6 to 8×10 -2 Torr; heating the dielectric substrate to a temperature of 600° C. to 1200° C.; initiating presputtering while protecting the substrate from any deposition with a protective cover; admitting cyanogen gas or a nitrogen-cyanogen gas mixture at a substantially constant volumetric flow rate of about 10 -6 Torr liters/sec into the reactor, wherein the cyanogen gas is admitted into the reactor at a constant flow rate which ranges from 10 -9 to 10 -6 Torr liters/sec; removing the protective-covering of the dielectric substrate after a partial pressure of about 5 microns of reactant gas is obtained in the reactor; applying a constant RF power density of about 10-20 watts/cm 2 to the niobium target in order to initiate reactive sputtering; forming a thin NbCN film of a desired thickness; cooling the reactor and the deposited film back to room temperature and pressure.
Claim 2
Independent Claim
221 words
A method for the preparation of superconducting thin films of niobium carbonitride of exceptional purity, comprising: assembling within a closed reactor a dielectric substrate and a pure niobium target; evacuating the reactor to a pressure of about 10 -10 Torr, while heating the components contained within the reactor so as to substantially eliminate all volatile impurities therefrom; admitting an inert gas into the reactor until the inert gas attains a pressure within the range of about 6 to 8×10 -2 Torr; heating the dielectric substrate to a temperature of 600° C. to 1200° C.; initiating presputtering while protecting the substrate from any deposition with a protective cover; admitting cyanogen gas or a nitrogen-cyanogen gas mixture at a substantially constant volumetric flow rate of about 10 -6 Torr liters/sec into the reactor, wherein the cyanogen gas is admitted into the reactor at a constant flow rate which ranges from 10 -9 to 10 -6 Torr liters/sec; removing the protective-covering of the dielectric substrate after a partial pressure of about 5 microns of reactant gas is obtained in the reactor; applying a constant RF power density of about 10-20 watts/cm 2 to the niobium target in order to initiate reactive sputtering; forming a thin NbCN film of a desired thickness; cooling the reactor and the deposited film back to room temperature and pressure.
Claim 3
Dependent Claim
13 words
The method of claim 1, in which the inert gas is ultrapure argon.
Claim 4
Dependent Claim
12 words
The method of claim 1, in which the dielectric substrate is sapphire.
Claim 5
Dependent Claim
27 words
The method of claim 1, in which the substrate is preheated to a temperature of about 1000° C. for a period of about 2 to 4 hours.
Claim 6
Dependent Claim
20 words
The method of claim 1, in which the preferred RF power density during presputtering is about 6 watts/cm 2 .
Claim 7
Dependent Claim
21 words
The method of claim 1 where the preferred RF power density during reactive sputtering is about 15 watts/cm 2 . A20
Claim 8
Dependent Claim
21 words
The method of claim 1 whereby the NbCN film deposited is of a thickness from about 200 to about 6000 A°.
Claim 9
Dependent Claim
15 words
The thin superconducting film on a dielectric substrate produced by the process of claim 1.
References Cited (Backward Citations)
US3912612A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-07-20 | 1985-01-19 | 1985-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-20 | 1989-01-19 | 1989-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-20 | 1993-01-19 | 1993-07-21 | $7700.00 | Window Closed / Lapsed |