Fabrication of all-NbN Josephson tunnel junctions using single crystal NbN films for the base electrodes

Author

Shoji, A.

Author_Institution

Electrotech. Lab., Ibaraki, Japan

Volume

27

Issue

2

fYear

1991

fDate

3/1/1991 12:00:00 AM

Firstpage

3184

Lastpage

3187

Abstract

All-NbN Josephson tunnel junctions with sputter-deposited magnesium oxide barriers have been fabricated using single-crystal NbN films for the base electrodes. Fabricated Josephson junctions have shown good tunneling characteristics with large gap voltages (5.6-5.8 mV), narrow gap widths (0.1-0.2 mV, from 30 to 70%), and small subgap leakage currents (V_m=20-30 mV, measured at 3 mV). The results of a measurement of a subgap structure for a fabricated junction suggest that the excess leakage currents of fabricated junctions are due to multiparticle tunneling through locally thin areas in the MgO barriers

Keywords

leakage currents; magnesium compounds; niobium compounds; sputter deposition; superconducting junction devices; 5.6 to 5.8 mV; Josephson tunnel junctions; NbN-MgO-NbN; base electrodes; fabrication; gap voltages; leakage currents; locally thin areas; multiparticle tunneling; narrow gap widths; single crystal NbN films; sputter deposition; tunneling characteristics; Electrodes; Fabrication; Leakage current; Niobium; Optical films; Sputtering; Substrates; Superconducting films; Temperature; Tunneling;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.133888

Filename

133888