• Prunnila, Mika
• Viisanen, Klaara
• Bohuslavskyi, Heorhii
• Generalov, Andrey A.
• Ma, Jian
• Möttönen, Mikko

Abstract

Electrostatically tunable Josephson field-effect transistors (JoFETs) are one of the most desired building blocks of quantum electronics. JoFET applications range from parametric amplifiers and superconducting qubits to a variety of integrated superconducting circuits. Here, we report on graphene JoFET devices fabricated with wafer-scale complementary metal-oxide-semiconductor (CMOS) compatible processing based on wet transfer of chemical vapour deposited graphene, atomic-layer-deposited Al$_{2}$O$_{3}$ gate oxide, and evaporated superconducting Ti/Al source, drain, and gate contacts. By optimizing the contact resistance down to170 $Ωμm$, we observe proximity-induced superconductivity in the JoFET channels with different gate lengths of 150 - 350 nm. The Josephson junction devices show reproducible critical current $I_{{C}}$ tunablity with the local top gate. Our JoFETs are in short diffusive limit with the $I_{{C}}$ reaching up to $\,$3 $μA$ for a 50 $μm$ channel width. Overall, the successful demonstration of CMOS-compatible 2D-material-based JoFET fabrication process is an important step towards graphene-based integrated quantum devices.

Topics

• impedance spectroscopy
• semiconductor
• superconductivity
• superconductivity