Silicon spin qubits are promising candidates for realising large scale quantum processors, benefitting from a magnetically quiet host material and the prospects of leveraging the mature silicon device fabrication industry. We report the measurement of an electron spin in a singly-occupied gate-defined quantum dot, fabricated using CMOS compatible processes at the 300 mm wafer scale. For readout, we employ spin-dependent tunneling combined with a low-footprint single-lead quantum dot charge sensor, measured using radiofrequency gate reflectometry. We demonstrate spin readout in two devices using this technique, obtaining valley splittings in the range 0.5-0.7 meV using excited state spectroscopy, and measure a maximum electron spin relaxation time (T1) of 9±3 s at 1 Tesla. These long lifetimes indicate the silicon nanowire geometry and fabrication processes employed here show a great deal of promise for qubit devices, while the spin-readout method demonstrated here is well-suited to a variety of scalable architectures.
@article{arxiv.2005.07764,
title = {Spin readout of a CMOS quantum dot by gate reflectometry and spin-dependent tunnelling},
author = {V. N. Ciriano-Tejel and M. A. Fogarty and S. Schaal and L. Hutin and B. Bertrand and Lisa Ibberson and M. F. Gonzalez-Zalba and J. Li and Y. -M. Niquet and M. Vinet and J. J. L. Morton},
journal= {arXiv preprint arXiv:2005.07764},
year = {2021}
}