Eur. Phys. J. B 23, 421-425 (2001)
https://doi.org/10.1007/s100510170032

Whole-wafer fabrication process for three-terminal double stacked tunnel junctions

¹ Dipartimento Scienze Fisiche, Università di Napoli "Federico II" , P.le Tecchio 80, 80125 Napoli, Italy
² INFM, UdR di Napoli, Piazzale Tecchio 80, 80125 Napoli, Italy
³ Dipartimento Ingegneria dell'Informazione, Seconda Università di Napoli, Via Roma 29, 81031 Aversa (CE), Italy
⁴ Istituto di Cibernetica del CNR, Via Toiano 6, 80078 Arco Felice, Napoli, Italy

Corresponding author: ^a peluso@na.infn.it

Received: 5 June 2001
Published online: 15 October 2001

Abstract

A new fabrication process for three-terminal superconducting devices consisting of two Josephson junctions in a stacked configuration is reported. The process is based on the deposition of the whole Nb/Al_xO_y/Nb-Al/Al_xO_y/Nb multilayer on a Si crystalline wafer without any vacuum breaking. Lift-off techniques, anodization processes and a SiO film deposition have been adopted for patterning and insulating the two tunnel stacked junctions. Devices have been characterized in terms of current-voltage (I-V) curves and Josephson critical current vs. the externally applied magnetic field. They show high quality factors (V_m values up to 65 mV at 4.2 K), and good current uniformity.