Properties of RF-sputtered Nb/Al-AlO/sub x//Nb Josephson SNAP junctions

Author

Lacquantii, V. ; Maggi, S. ; Monticone, E. ; Steni, R.

Author_Institution

Istituto Elettrotecnico Nazionale Galileo Ferraris, Torino, Italy

Volume

6

Issue

1

fYear

1996

fDate

3/1/1996 12:00:00 AM

Firstpage

24

Lastpage

31

Abstract

A detailed analysis of the properties of Nb/Al-AlO/sub x//Nb Josephson tunnel junctions fabricated with a modified SNAP process is presented. Selective niobium anodization has been used not only as on-line monitoring of the junction quality, through depth profiling anodization spectroscopy, but also to achieve a controlled reduction of the junction area at micrometer level by a proper choice of the anodization current. The dependence of the most relevant junction electrical parameters on fabrication variables has been investigated. With this fabrication process, junctions with V/sub m/ as high as 60 mV and current densities J/sub c//spl les/2000 A/cm/sup 2/ at 4.2 K are routinely obtained, thus demonstrating its feasibility for high frequency mixer and voltage standard applications.

Keywords

Josephson effect; aluminium; aluminium compounds; anodisation; niobium; sputtered coatings; superconductor-insulator-superconductor devices; Nb-Al-AlO-Nb; Nb/Al-AlO/sub x//Nb Josephson tunnel junctions; RF sputtering; SNAP process; depth profiling anodization spectroscopy; electrical parameters; fabrication; high frequency mixer; on-line monitoring; selective niobium anodization; voltage standard; Current density; Etching; Fabrication; Frequency; Geometry; Josephson junctions; Niobium; Plasma applications; Spectroscopy; Voltage;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.488277

Filename

488277