Fabrication of submicron Nb/AlO/sub x/-Al/Nb tunnel junctions using focused ion beam implanted Nb patterning (FINP) technique

Author

Akaike, H. ; Watanabe, T. ; Nagai, N. ; Fujimaki, A. ; Hayakawa, H.

Author_Institution

Dept. of Electron., Nagoya Univ., Japan

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

2310

Lastpage

2313

Abstract

We have successfully fabricated 0.2 /spl mu/m/sup 2/ Nb/AlO/sub x//Nb tunnel junctions using the focused-ion-beam implanted Nb patterning (FINP) technique for junction definition. The success was due to improvement of the edge profile of the counter electrode. The vertical edge profile was realized with the large etching selectivity of Ga implanted Nb over unimplanted Nb by controlling the reactive neutrals in the plasma. The critical current I/sub c/ and the quality parameter V/sub m/ of 0.2 /spl mu/m/sup 2/ junctions were 10.5 /spl mu/A and 11 mV, respectively. The R/sub sg//R/sub n/ was 12. The maximum to minimum spread in I/sub c/ of 60 series junctions with areas of 0.5 /spl mu/m/sup 2/ was /spl plusmn/10%.<>

Keywords

Josephson effect; aluminium; aluminium compounds; focused ion beam technology; ion implantation; niobium; sputter etching; 0.2 micron; Ga; Nb-AlO-Al-Nb; counter electrode; critical current; fabrication; focused ion beam implanted Nb patterning; plasma etching selectivity; quality parameter; submicron Nb/AlO/sub x/-Al/Nb tunnel junctions; vertical edge profile; Counting circuits; Critical current; Electrodes; Etching; Fabrication; Ion beams; Josephson junctions; Niobium; Plasma applications; SQUIDs;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.403047

Filename

403047