Niobium trilayer process for superconducting circuits

A Nb-AlO/sub x/-Nb trilayer process was developed that consistently produces junctions with V/sub m/>40 mV. Critical current density was controlled reproducibly from 200 to 7000 A/cm/sup 2/ by controlling the oxygen pressure in the process chamber during thermal oxidation of the aluminum. A multilayer AlO/sub x/ barrier was used to produce junctions for Josephson circuit applications requiring low critical currents ( 40 mV) Josephson junctions have been fabricated with low stress ( >