NOVEL TECHNIQUE FOR PREPARATION OF TUNNEL JUNCTION BARRIERS USING ELECTROCHEMICAL ANODIZATION.

A novel method has been developed for preparing both Josephson and single particle tunnel junctions. This technique has been applied to Sn-Sn//xO//y-metal films where the tin oxide barrier is formed on the surface of a freshly evaporated Sn film by electrochemical anodization. By varying the anodization parameters, the junction resistances can be controlled over more than three orders of magnitude: i. e. , from less than 10** minus **4 ohm-cm**2 to 0. 1 ohm-cm**2. In each instance, high quality junctions with nearly ideal I-V characteristics and low leakage currents have been produced. Low resistance Josephson junctions have been fabricated whose critical currents scale with junction resistance and modulate with applied magnetic field in the familiar Fraunhofer-like diffraction pattern.