Abstract
Josephson junctions, which are regions of weak electrical connection between two superconductors, are the active elements of very sensitive thin-film magnetometers. Junctions are fabricated by growing barriers of native oxide on thin Nb films and depositing a layer of Pbln alloy on top. High sensitivity magnetometers require junctions of small area, and to achieve this, edge junctions are fabricated in which one dimension is defined by the thickness of the Nb and the other is set by the limit of optical lithography. An edge with a suitable angle is produced by reactive ion etching using 5 vol % O 2 in CF 4 in a parallel plate rf plasma etcher. Details of etch rates and edge profiles are given. The barrier is formed by a cleaning and oxidation process in an rf plasma at a pressure of 10 −6 bar. Details of the design of a purpose built rf cathode and the run-to-run reproducibility of junction characteristics are given. Different oxidation times and bias voltages are necessary to produce a given oxide thickness on a sloping edge of Nb, as compared to a planar surface, and an explanation for this is proposed. Examples are described of magnetometers made using the above processes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
