Research on Superconducting Signal Processing Devices.
Abstract
An understanding of the role of alloying elements in lead thin films for use as Josephson junctions was achieved and thermally cyclable devices were made. Gold is one of the elements which strongly inhabit the movement of grain boundaries and thus prevent the growth of hillocks and whiskers on the film which would puncture the thin oxide barrier. A new technology in which thin silicon membranes supported by a surrounding frame can be used for device fabrication was developed. This includes a double-etching scheme to achieve even submicron size membranes having thickness of no more than a few hundred angstroms. We have shown that advantages can be had by fabricating Schottk and super-Schottky diodes on such membranes. Also, Josephson junctions made this way show promise of great design flexibility and may develop into the best Josephson device for mixing and detection. Two ways of making double weak superconducting links for possible use as switching elements were tested. It appears that the impedance level is lower than would be desired for that application for the dimensions used so far but fabrication by electron lithography would increase it. The semiconductor barrier is analyzed, as a possible Josephson junction switching element and it appears to have some advantages. One of these is a lower Q for the junction cavity; our analysis shows about two orders of magnitude improvement in this regard over oxide-barrier junctions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1975
- Accession Number
- ADA019672
Entities
People
- T. Van Duzer
Organizations
- University of California, Berkeley