A robust fabrication process for a refractory integrated SQUID gradiometer

Author

Hutson, D. ; Weston, R.G. ; Bain, R.J.P. ; Lawrenson, M.J. ; Pegrum, C.M. ; Popova, K. ; Scarfone, R.

Author_Institution

Dept. of Phys. & Appl. Phys., Strathclyde Univ., Glasgow, UK

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

2295

Lastpage

2298

Abstract

We describe a process used successfully to fabricate large second-order planar gradiometers with integrated DC SQUIDs on two-inch silicon wafers. All the refractory materials (Nb, Mo and SiO/sub 2/) are deposited by magnetron sputtering. The Josephson junctions are based on the well-established Nb/AlO/sub x//Nb trilayer technology. All Nb layers are patterned by Reactive Ion Etching using a procedure optimized by experimental design. Since only one gradiometer can fit on a wafer, extra care had to be taken in both the design of the device and the fabrication process to ensure that the yield was high. Excellent process latitude is achieved by sufficient built-in design margins to accommodate any tolerance difficulties during fabrication.<>

Keywords

SQUID magnetometers; refractories; sputter etching; sputtered coatings; 2 inch; Josephson junctions; Mo; Nb-AlO-Nb; Nb/AlO/sub x//Nb trilayer technology; Si; SiO/sub 2/; built-in design margins; fabrication; integrated DC SQUIDs; magnetron sputtering; process latitude; reactive ion etching; refractory materials; second-order planar gradiometers; silicon wafers; tolerance; yield; Design optimization; Fabrication; Josephson junctions; Magnetic materials; Niobium; Robustness; SQUIDs; Silicon; Sputter etching; Sputtering;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.403044

Filename

403044