Title :
Submicron area NbN/MgO/NbN tunnel junctions for SIS mixer applications
Author :
Leduc, H.G. ; Judas, A. ; Cypher, S.R. ; Bumble, B. ; Hunt, B.D. ; Stern, J.A.
Author_Institution :
Jet Propulsion Lab., California Inst. of Technol., Pasadena, CA, USA
fDate :
3/1/1991 12:00:00 AM
Abstract :
The development of submicron area mixer elements for operation in the submillimeter wave range is discussed. High-current-density NbN/MgO/NbN tunnel junctions with areas down to 0.1 μm2 have been fabricated in both planar and edge geometries. The planar junctions were fabricated from in situ deposited trilayers using electron-beam lithography to pattern submicron area mesas. Modifications of fabrication techniques used in larger-area NbN tunnel junctions are required and are discussed. The NbN/MgO/NbN edge junction process using sapphire substrates has been transferred to technologically important quartz substrates using MgO buffer layers to minimize substrate interactions. The two junction geometries are compared and contrasted in the context of submillimeter wave mixer applications
Keywords :
magnesium compounds; mixers (circuits); niobium compounds; solid-state microwave devices; superconducting junction devices; Al2O3; EHF; MgO buffer layers; NbN-MgO-NbN; SIS mixer; SiO2; edge geometries; edge junction process; electron-beam lithography; fabrication techniques; in situ deposited trilayers; junction geometries; planar geometries; planar junctions; quartz substrates; sapphire substrates; sub-MM-waves; submicron area mesas; submicron area mixer elements; submillimeter wave mixer; submillimeter wave range; Current density; Fabrication; Geometry; Laboratories; Lithography; Space technology; Submillimeter wave technology; Substrates; Superconducting films; Superconducting materials;
Journal_Title :
Magnetics, IEEE Transactions on
