A novel architecture paves the way to large-scale integration of qubits arrays

A joint work between EPFL, University of Basel and IBM Zürich, enabled by the NCCR SPIN, has been presented by Fabio Bersano at the very selective VLSI Tehnology Symposium (https://www.vlsisymposium.org/program.html) on June 15, in Kyoto, Japan in the Technology Session on Quantum Computing and Cryo-CMOS.

This work reported the first integration of ferromagnetic nanosized cobalt barrier gates in quantum dots arrays on FD-SOI nanowires. The proposed novel structure enhances both driving and addressability, while minimizing decoherence fields for electron spin qubits. The double dot experimental data show stable quantum confinement at 10mK and full multi-gate FET functionality. Based on calibrated magnetic simulations, the work explored the advantages of exploiting electrical and ferromagnetic gates. Finally, this work achieved a record small dot-magnet distance below 10nm, with a footprint of the magnetic gates of 30x70nm2 on dots area, the smallest reported to date on a qubit structure, with a Rabi frequency of 282MHz and qubit addressability of 1.069GHz. This novel architecture achieved in the NCCR SPIN paves the way to large-scale integration of qubits arrays, with excellent magnetic control.