  Quantum computing's greatest challenge is scaling up. Several decades ago,
classical computers faced the same problem and a single solution emerged:
very-large-scale integration using silicon. Today's silicon chips consist of
billions of field-effect transistors (FinFETs) in which current flow along the
fin-shaped channel is controlled by wrap-around gates. The semiconductor
industry currently employs fins of sub-10$\,$nm width, small enough for quantum
applications: at low temperature, an electron or hole can be trapped under the
gate and serve as a spin qubit. An attractive benefit of silicon's advantageous
scaling properties is that quantum hardware and its classical control circuitry
can be integrated in the same package. This, however, requires qubit operation
at temperatures greater than 1$\,$K where the cooling is sufficient to overcome
the heat dissipation. Here, we demonstrate that a silicon FinFET is an
excellent host for spin qubits that operate even above 4$\,$K. We achieve fast
electrical control of hole spins with driving frequencies up to 150$\,$MHz and
single-qubit gate fidelities at the fault-tolerance threshold. The number of
spin rotations before coherence is lost at these "hot" temperatures already
matches or exceeds values on hole spin qubits at mK temperatures. While our
devices feature both industry compatibility and quality, they are fabricated in
a flexible and agile way to accelerate their development. This work paves the
way towards large-scale integration of all-electrical and ultrafast spin
qubits.
