CONTROL AND REPRODUCIBILITY OF C-AXIS MICROBRIDGES

Vertical c-axis microbridges, with dimensions comparable to the penetr ation depth (lambda(3)), have been investigated experimentally and the oretically, Josephson-like effects are observed due to coherent motion of vortices across the bridge, Both the an-chip and chip to chip repr oducibility has been improved ft om previous reports by process optimi sation, Within an array it is highly dependent on the oxygenation stat e and the temperature of tile sample. Although the spread in parameter s within an array of standard junctions is almost good enough to fabri cate many circuits of interest, the I-c is too high and the R-n too lo w for many logic applications, In an attempt to reduce the coupling st rength, the growth temperature of a region of the material in the micr obridge has been varied. Initial results suggest I-c can be reduced an d R-n increased to a level which, with further optimisation, might be useful for logic applications, while the reproducibility was not adver sely affected.