2001/11/19 by M. Faucher, T. Fournier, Thierry Fournier +8
Physics and Astronomy · #Anodizing #Composite material #Condensed matter physics #Fabrication #Josephson effect #Lithography #Materials science #Metallurgy #Nanotechnology #Niobium #Niobium nitride #Nitride #Optoelectronics #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Superconductivity #Supercurrent #Surface and Thin Film Phenomena #cond-mat.mes-hall #cond-mat.supr-con
paper · pdf · doi:10.1016/s0921-4534(01)01168-6
published as Physica C 368, 211 (2002) · 22 pages, 8 figures
arxiv created 2001/11/19 · openalex publication_date 2002/03/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present a fabrication method of superconducting quantum interference devices (SQUIDs) based on direct write lithography with an Atomic Force Microscope (AFM). This technique involves maskless local anodization of Nb or NbN ultrathin films using the voltage biased tip of the AFM. The SQUIDs are of weak-link type, for which two geometries have been tested: Dayem and variable thickness nanobridges. The magnetic field dependence of the maximum supercurrent Ic(flux) in resulting SQUIDs is thoroughly measured for different weak link geometries and for both tested materials. It is found that the modulation shape and depth of Ic(flux) curves are greatly dependent on the weak link size. We analyze the results taking into account the kinetic inductance of nanobridges and using the Likharev-Yakobson model. Finally we show that the present resolution reached by this technique (20nm) enables us to fabricate Nb weak-links which behavior approaches those of ideal Josephson junctions.