Nanoscale SNS junction fabrication in superconductor-normal metal bilayers

We have developed a reliable and versatile technique for fabricating SNS junctions in a superconductor-normal metal bilayer using a focused ion beam microscope (FIB) in conjunction with an in-situ resistance measurement technique. This technique offers a simple method for creating multi-junction dev...

Full description

Saved in:
Bibliographic Details
Published in:IEEE transactions on applied superconductivity 2001-03, Vol.11 (1), p.1126-1129
Main Authors: Hadfield, R.H., Burnell, G., Booij, W.E., Lloyd, S.J., Moseley, R.W., Blamire, M.G.
Format: Article
Language:English
Subjects:
Applied sciences
Electrical resistance measurement
Electronics
Exact sciences and technology
Fabrication
Ion beams
Josephson junctions
Measurement techniques
Niobium
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
SQUIDs
Superconducting devices
Superconducting microwave devices
Transmission electron microscopy
Voltage
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We have developed a reliable and versatile technique for fabricating SNS junctions in a superconductor-normal metal bilayer using a focused ion beam microscope (FIB) in conjunction with an in-situ resistance measurement technique. This technique offers a simple method for creating multi-junction devices (SQUIDs, 3-terminal devices, arrays) with high integration densities. In this paper we discuss recent results from devices created in Nb-Cu tracks by cutting 50 nm trenches in the top Nb layer to weaken the superconducting coupling. Cuts of depths between 60 and 100% of the Nb thickness yield reproducible junctions with current voltage (I(V)) characteristics in accordance with the resistively-shunted-junction (RSJ) model, characteristic voltage I/sub C/R/sub N//spl sim/50 /spl mu/V at 4.2 K and excellent microwave response. A thorough study has been carried out of the effect on device parameters of varying the Cu layer thickness (0-175 nm). In addition transmission electron microscopy (TEM) studies have been carried out on the device structure. A two-channel model of device operation has been developed and related to the results of I/sup C/R/sub N/(T) measurements (down to 350 mK) on selected devices.
ISSN:1051-8223
1558-2515
DOI:10.1109/77.919546