Physics of Preparation of Josephson Barriers

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Abstract
Josephson barriers of the tunneling type are usually prepared by oxidation in room environment, but they degrade after storage at room temperature for a few days. This paper describes a preparation technique based on an oxygen glow discharge which renders stable, reproducible superconductive tunneling devices (STDs). The barrier may also consist of organic molecules (KPR, monocarbonic acids); lead serves as the superconducting metal. Simplified models are used to discuss the main features and advantages of the glow‐discharge technique. Extensive investigation has shown that arrays of STDs can be fabricated using the photoresist technique developed by Pritchard et al. The current‐voltage and magnetic‐field characteristics of these arrays are examined; it was found that they did not change during array storage at room temperature for more than 240 days and repeated temperature cycling from room temperature to 4.2°K.