PROXIMITY EFFECT TUNNEL JUNCTIONS WITH BARRIERS FORMED FROM AMORPHOUS ALLOYS

Nous avons fabriqué des jonctions tunnel multi-réseaux dans lesquelles l'électrode de base est un alliage amorphe de Nb-Si ou de Nb-Al déposé sur une surface de niobium Ces jonctions ont une capacitance plus faible que celles fabriquées à partir de niobium pur. De plus, en-dessous du gap, nous n'observons que de très faibles courants d'excès.Superconducting tunnel junctions with multilayer base electrodes have been constructed in which the surface of the base electrode is composed of an amorphous alloy (≤ 100 Å thick). Base electrodes consisting of Nb with a surface layer of amorphous Nb-Si or Nb-Al have been fabricated. Tunnel barriers grown from these alloys have shown reduced capacitance when compared to barriers formed on pure Nb surfaces. In addition, low excess currents have been observed in these junctions ; however, the junction characteristics are sensitive to the thickness and composition of this amorphous layer