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Thin Film Resistors for Superconducting Circuits

IP.com Disclosure Number: IPCOM000050920D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Ames, I: AUTHOR [+2]

Abstract

Thin film resistors for use in superconducting circuits containing Josephson tunneling junctions and superconducting Nb and/or Pb-alloy thin film layers can be prepared through the use of thin films of Ti. Illustratively, Ti films are prepared by vacuum deposition at a pressure of about 10/-8/ to about 10/-6/ Torr, a range over which their sheet resistance at 4.2 degrees K is relatively insensitive to pressure during film deposition. After annealing at a temperature between 70 and 200 degrees C for stabilization, a sheet resistance at 4.2 degrees K of from about 2 to 3 ohms per square cm was obtained through use of an 800 Angstroms thick Ti film strip in contact with 2,000 Angstroms thick superconducting Nb thin film strips.

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Thin Film Resistors for Superconducting Circuits

Thin film resistors for use in superconducting circuits containing Josephson tunneling junctions and superconducting Nb and/or Pb-alloy thin film layers can be prepared through the use of thin films of Ti. Illustratively, Ti films are prepared by vacuum deposition at a pressure of about 10/-8/ to about 10/-6/ Torr, a range over which their sheet resistance at 4.2 degrees K is relatively insensitive to pressure during film deposition. After annealing at a temperature between 70 and 200 degrees C for stabilization, a sheet resistance at 4.2 degrees K of from about 2 to 3 ohms per square cm was obtained through use of an 800 Angstroms thick Ti film strip in contact with 2,000 Angstroms thick superconducting Nb thin film strips. Resistors having higher sheet resistances can be obtained by using thinner Ti films which are compatible with use beneath or above the Nb.

Annealing can also be used to reach a targeted resistance value. From examination of an observed decrease in resistance with annealing time at temperatures up to 200 degrees C, it was found that the annealing behavior could be expressed in terms of an Arrhenius function with an activation energy of approximately 1 eV. An estimate could be made using that activation energy of the time which would be required for a resistor, which had been annealed at 150 degrees C for 3 hours, to achieve a targeted resistance, to subsequently undergo a li decrease in resistan...