RF response of high RF-T/sub c/ SNS Josephson microbridges suitable for integrated circuit applications

A simple process has been developed for microfabricating high transition temperature superconductor-normal-metal-superconductor (SNS) Josephson devices that operate up to 80 K and are reasonably ideal at 43 K. Bridge resistances greater than 10 Omega and critical-current-normal-state resistance (I/sub c/R/sub N/) products greater than 1 mV have been achieved. Clearly defined RF steps have been observed, with power dependence qualitatively similar to theoretical predictions. The fabrication process and the device characteristics are suitable for superconducting integrated circuit applications such as millimeter-wave Josephson oscillators, parametric amplifiers, and single-flux quantum digital logic.