Investigation of etching techniques for superconductive Nb/Al-Al/sub 2/O/sub 3//Nb fabrication processes

Author

Lichtenberger, A.W. ; Lea, D.M. ; Lloyd, F.L.

Author_Institution

Dept. of Electr. Eng., Virginia Univ., Charlottesville, VA, USA

Volume

3

Issue

1

fYear

1993

fDate

3/1/1993 12:00:00 AM

Firstpage

2191

Lastpage

2196

Abstract

Wet etching, CF/sub 4/ and SF/sub 6/ reactive ion etching (RIE), RIE/wet hybrid etching, Cl-based RIE, ion milling and liftoff techniques have been investigated for use in superconductive Nb/Al-Al/sub 2/O/sub 3//Nb fabrication processes. High-quality superconductor-insulator junctions have been fabricated using a variety of these etching methods; however, each technique offers distinct tradeoffs for a given process an wafer design. In particular, it was shown that SF/sub 6/ provides an excellent RIE chemistry for low-voltage anisotropic etching of Nb with high selectivity to Al. The SF/sub 6/ tool has greatly improved the trilevel resist junction insulation process. Excellent repeatability, selectivity with respect to quartz, and submicron resolution make Cl/sub 2/+BCl/sub 3/+CHCl/sub 3/ RIE a very attractive process for trilayer patterning.<>

Keywords

alumina; aluminium; etching; niobium; sputter etching; superconducting junction devices; type II superconductors; Nb-Al-Al/sub 2/O/sub 3/Nb junctions; hybrid dry/wet etching; ion milling; liftoff techniques; low-voltage anisotropic etching; reactive ion etching; repeatability; selectivity; submicron resolution; superconductor-insulator junctions; trilayer patterning; trilevel resist junction insulation; Anisotropic magnetoresistance; Chemistry; Fabrication; Josephson junctions; Milling; Niobium; Process design; Resists; Superconductivity; Wet etching;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.233938

Filename

233938