Niobium microbridges for SQUID applications

Niobium microbridges developed for SQUID applications are discussed. We can reliably produce superconducting films down to a thickness of 50 Angstroms using rf bias sputtering techniques. Bridge patterns of submicron width are produced through electron lithography with a scanning electron microscope/flying spot scanner combination. The transition from macroscopic leads to the microbridge is made with a multiple exposure technique. The pattern is reproduced in the superconducting niobium films by sputter etching.