Josephson Tunnel-Junction Electrode Materials

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Science  23 May 1980:
Vol. 208, Issue 4446, pp. 944-950
DOI: 10.1126/science.208.4446.944


Josephson superconducting devices of the tunnel-junction type have exciting potential for use in building ultrahigh-speed computers. We consider the properties of superconducting metals that are needed for such devices that would be used in integrated computer circuits operated at a temperature near absolute zero. Recent advances in lead-alloy thin-film materials are described that have led to substantial improvements in lead-alloy Josephson device reliability. The properties of a Pb0.84In0.12Au0.04 alloy, of Nb, and of Nb3Sn are discussed as examples of three different groups of materials that are of interest. Investigations of lead-alloy and niobium devices have progressed to the point that it is evident that they have good potential for fabricating integrated circuits containing large numbers of devices.