'Sail' high temperature superconductor digital logic: improvements and analysis

High-temperature superconductor step-edge junctions have been incorporated into a series array interferometer logic (SAIL) design, resulting in improvements in voltage and temperature performance. The junctions provide an I/sub c/R/sub n/ (critical-current normal-resistance) product of 300 mu V at 65 K, which makes it possible to have 100 mu V switching of gates at cryocooler temperatures. With improvements in I/sub c/ uniformity, the architecture should allow use in gate arrays. The present analysis indicates that the current I/sub c/R/sub n/ is sufficient to run up to 10 GHz; while this is slow compared to other superconducting logic families, it is competitive with bipolar semiconductors, with good prospects for improvement. DC design models have been compared to JSIM simulations, and a sketch of the theoretical margins is presented in this context.<
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