A DC SQUID with intrinsically shunted submicron junctions near the hysteretic limit exhibiting an extremely large dV/d phi transfer function

A fabrication process yielding submicron-scale Josephson junctions has been developed. The junction consists of two metal striplines lying in line and separated by a vertical barrier. Thus the contact area is determined by the width and thickness of the striplines. The capacitive coupling is only due to the small contact area, because there is no layer overlap. The process was applied to all-Nb thin-film junction technology with nitrided Si barriers. The I-V (current-voltage) curves of these junctions show the characteristic features of superconductor-normal-superconductor contacts. DC SQUIDs (superconducting quantum interference devices) made of these junctions exhibit characteristics competitive with those of high-quality tunnel-junction DC SQUIDs.<
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