Title :
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
fDate :
6/1/1995 12:00:00 AM
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;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
