Abstract: In electrical circuitry, and particularly superconducting circuitry including Josephson tunnelling devices, it is often necessary to provide solder contacts to electrical lines, where the electical lines would be destroyed if there were interdiffusion between the lines and the solder. To avoid this problem, a laterally extending metallic layer is used as a diffusion barrier between the solder land and the electrical line which can be a superconducting line. The diffusion barrier is comprised of a refractory metal which has a first portion electrically contacting the solder land and a second, laterally displaced portion, electrically contacting the electrical line. An insulating protective layer on the diffusion barrier layer separates the solder land and the electrical line.

Abstract: Thin film electrodes particularly suited for Josephson devices of improved thermal cyclability are prepared by depositing thin films of superconductive metal and an intermetallic compound former on a substrate held at a temperature below about 100.degree. K. and at a pressure below about 1.times.10.sup.-7 Torr so that intermetallic compound formation occurs at the grain boundaries of the metal to inhibit grain growth. The thin film electrodes are characterized by median grain size <100 nm.