Accession Number : ADA136722

Title :   Thin Film Technology of High-Critical-Temperature Superconducting Electronics.

Descriptive Note : Annual rept. 1 Aug 82-30 Oct 83,


Personal Author(s) : Talvacchio,J ; Braginski,A I ; Gavaler,J R ; Janocko,M A ; Manocha,A S

PDF Url : ADA136722

Report Date : 05 Dec 1983

Pagination or Media Count : 74

Abstract : The objective of the first year's work was to investigate A15 superconductor/barrier oxide interfaces, identify oxide depth profiles, and determine resulting tunneling characteristics using soft tunnel junction counterelectrodes. Bilayers consisting of Nb and vanadium-silicon (A15) base electrodes and thin Y, Al, and Si barriers have been deposited in-situ and oxidized in humid air for up to three days. XPS analysis was used to compare the barrier coverage, uniformity, oxidation, and ability to protect the base electrode from oxidation for three deposition techniques: dc magnetron sputtering, dc diode sputtering, and reactive diode sputtering followed by pyrolysis. Y and Al have been found to be fully oxidized due to long oxidation times. In the above conditions the overlayers did not protect the superconductors from oxidation/hydration, and the surface of oxidized vanadium-silicon was also degraded by atomic segregation. The tunneling I-V characteristics exhibited very high leakage currents also suggestive of incomplete superconductor coverage by the metallic overlayer. Mo-Re was investigated for its potential as a high-critical-temperature counterelectrode. A very low oxidation rate was found indicating potential compatibility with yttrium hydroxide-sealed barriers. Low temperature growth (60 C) of MoRe (86 at. % Mo) with only a 5% decline in critical temperature has been demonstrated. Work will continue in a closed system to eliminate the base superconductor degradation, reduce leakage and study high-critical-temperature counterelectrodes.

Descriptors :   *Superconductors, *Josephson junctions, *Tunneling(Electronics), Thin films, Sputtering, Electrodes, Oxidation, Vanadium, Niobium, Molybdenum, Fabrication, Spectroscopy

Subject Categories : Electrical and Electronic Equipment
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE