Title :
Niobium nitride Josephson junction process development
Author :
Murduck, J.M. ; DiMond, J. ; Dang, C. ; Chan, H.
Author_Institution :
TRW Space & Technol. Group, Redondo Beach, CA, USA
fDate :
3/1/1993 12:00:00 AM
Abstract :
NbN/MgO/NbN tunnel junction fabrication has been developed using statistical experimental design for insertion into a Josephson LSI (large-scale integration) fabrication technology. Junction deposition conditions have been studied and correlated with structural characterization and junction I-V measurements. Josephson junctions with sum gaps as large as 5.0 mV and junction quality factor of 47 mV have been produced. Current density uniformity, a critical parameter in circuit design, has also been investigated. I/sub c/(O) uniformity at 4.2 K of a 4000 junction array was within sigma =3.1% and was +or-10% across 1 in/sup 2/. The utility of this junction process has been demonstrated by insertion into a standard circuit fabrication process that has produced logic circuit operation above 10 K.<>
Keywords :
Josephson effect; large scale integration; niobium compounds; superconducting integrated circuits; superconducting junction devices; superconducting logic circuits; type II superconductors; I-V measurements; Josephson junction; LSI fabrication; NbN-MgO-NbN tunnel junction; current density uniformity; logic circuit operation; process development; statistical experimental design; structural characterization; Circuit synthesis; Current density; Design for experiments; Fabrication; Integrated circuit measurements; Josephson junctions; Large scale integration; Logic circuits; Niobium compounds; Q factor;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
