Bicrystal submicrometer Josephson junctions and dc SQUIDs

Abstract

Submicrometer Josephson junctions and dc SQUIDs with such junctions have been prepared on symmetrical 24/spl deg/ bicrystal substrates and were electrically characterized. The submicrometer structures are patterned using e-beam lithography and a C/Ti/e-beam resist mask system. Junctions with dimensions down to about 350 nm show no degradation of their superconducting properties at 77 K, when patterned at low temperatures. Series connections of directly coupled SQUIDs with large (110-160 pH) coupling-inductance, prepared with 0.5 /spl mu/m wide junctions show flux-to-voltage transfer function values up to 100 /spl mu/V//spl Phi//sub 0/. For these SQUIDs, typical white noise levels of 10 /spl mu//spl Phi//sub 0///spl radic/Hz are measured at 77 K.