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We show how to measure and manipulate a single spin in a CMOS device fabricated in a pre-industrial 300 mm CMOS foundry. The device can be used as a spin quantum bit working at very low temperature. The spin manipulation is done by a microwave electric field applied directly on a gate. The presented results are a proof-of-principle demonstration of the possibility to define qubits by means of conventional industrial fabrication processes., Comment: Published in "Emerging Devices for Low-Power and High-Performance Nanosystems; Physics, Novel Functions, and Data Processing" Edited by Simon Deleonibus, Pan Stanford Publisher 2018

Two-level quantum systems with strong spin-orbit coupling allow for all-electrical qubit control and long-distance qubit coupling via microwave and phonon cavities, making them of particular interest for scalable quantum information technologies. In silicon, a strong spin-orbit coupling exists within the spin-3/2 system of acceptor atoms and their energy levels and properties are expected to be highly tunable. Here we show the influence of local symmetry tuning on the acceptor spin-dynamics, measured in the single-atom regime. Spin-selective tunneling between two coupled boron atoms in a commercial CMOS transistor is utilised for spin-readout, which allows for the probing of the two-hole spin relaxation mechanisms. A relaxation-hotspot is measured and explained by the mixing of acceptor heavy and light hole states. Furthermore, excited state spectroscopy indicates a magnetic field controlled rotation of the quantization axes of the atoms. These observations demonstrate the tunability of the spin-orbit states and dynamics of this spin-3/2 system., Comment: 7 pages, 4 figures. Supplementary information: 6 pages, 5 figures

We report CMOS-compatible quantized current sources (electron pumps) fabricated with nanowires (NWs) on 300 mm SOI wafers. Unlike other Al, GaAs or Si based metallic or semiconductor pumps, the fabrication does not rely on electron-beam lithography. The structure consists of two gates in series on the nanowire and the only difference with the SOI nanowire process lies in long (40 nm) nitride spacers. As a result a single, silicided island gets isolated between the gates and transport is dominated by Coulomb blockade at cryogenic temperatures thanks to the small size and therefore capacitance of this island. Operation and performances comparable to devices featuring e-beam lithography is demonstrated in the non-adiabatic pumping regime, with a pumping frequency up to 300 MHz. We also identify and model signatures of charge traps affecting charge pumping in the adiabatic regime. The availability of quantized current references in a process close to the 28FDSOI technology could trigger new applications for these pumps and allow to cointegrate them with cryogenic CMOS circuits, for instance in the emerging field of interfaces with quantum bits.

Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal-oxide-semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot (QD) encoding a hole spin qubit, the second one a QD used for the qubit readout. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. Our result opens a viable path to qubit up-scaling through a readily exploitable CMOS platform., Comment: 12 pages, 4 figures

We report on dual-gate reflectometry in a metal-oxide-semiconductor double-gate silicon transistor operating at low temperature as a double quantum dot device. The reflectometry setup consists of two radio frequency resonators respectively connected to the two gate electrodes. By simultaneously measuring their dispersive responses, we obtain the complete charge stability diagram of the device. Electron transitions between the two quantum dots and between each quantum dot and either the source or the drain contact are detected through phase shifts in the reflected radio frequency signals. At finite bias, reflectometry allows probing charge transitions to excited quantum-dot states, thereby enabling direct access to the energy level spectra of the quantum dots. Interestingly, we find that in the presence of electron transport across the two dots the reflectometry signatures of interdot transitions display a dip-peak structure containing quantitative information on the charge relaxation rates in the double quantum dot.