A hot hole spin qubit in a silicon FinFET*

Quantum computers promise an exponential speedup for certain computational tasks. Silicon-based spin qubits are among the prime candidates for implementing large-scale quantum circuits by leveraging widely deployed industrial CMOS technology. Furthermore, qubit operation at temperatures above 1K allows for on-chip integration of classical control electronics [Petit et al. & Yang et al., Nature 580, 350&355 (2020)].
Here, we demonstrate a hole spin qubit integrated in a silicon fin-field effect transistor (FinFET)[Geyer et al., arXiv:2007.15400 (2020)] operating at temperatures as high as 4.2K. Spin-orbit mediated electric-dipole spin resonance is used for fast (150MHz) all-electrical qubit control. A spin dephasing time of T₂*=150ns is measured which increases by a factor of 2 when cooling down to 1.5K. The qubit can be decoupled from low-frequency noise using dynamical decoupling sequences to increase the coherence time by a factor of 10. Randomized benchmarking using a series of Clifford gates allows to determine a single-gate fidelity of 98.9%(97.9%) at 1.5K(4.2K).
These results establish high-temperature hole spin qubits in silicon FinFETs as a potential platform for scalable quantum computing.