Method of making an improved superconducting quantum interference device
AssigneeThe United States of America as represented by the United States Energy Research and Development Administration
InventorsCheng-Teh Wu, Charles M. Falco, Robert T. Kampwirth
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Abstract
An improved superconducting quantum interference device is made by sputtering a thin film of an alloy of three parts niobium to one part tin in a pattern comprising a closed loop with a narrow region, depositing a thin film of a radiation shield such as copper over the niobium-tin, scribing a narrow line in the copper over the narrow region, exposing the structure at the scribed line to radiation and removing the deposited copper.
Claims8
A method of making a thin-film SQUID on a substrate comprising the following steps:
- sputtering an alloy of three parts niobium to one part tin in a desired closed loop pattern on the substrate;
- depositing a shielding material over the sputtered alloy;
- removing a portion of the shielding material in a thin line across said loop in a desired region;
- exposing the line to particle radiation;
- and
- removing the shielding material.
A method of making a thin-film SQUID on a substrate of sapphire comprising the steps of:
- sputtering an alloy of three parts niobium to one part tin to a thickness in the range of 20 to 500 nanometers on the substrate;
- photoetching the alloy to leave a closed loop with a narrow region;
- depositing copper on the alloy to a thickness of about 400 nonometers;
- scratching substantially through the copper with a razor blade to cross the narrow region;
- exposing the scratched area to radiation by alpha particles at an energy of about 50 KeV and a flux of about 10.sup.14 ions per square centimeter;
- and
- removing the copper with nitric acid.
Dependencies are inferred from the claim text.