  Silicon spin qubits promise to leverage the extraordinary progress in silicon
nanoelectronic device fabrication over the past half century to deliver
large-scale quantum processors. Despite the scalability advantage of using
silicon technology, realising a quantum computer with the millions of qubits
required to run some of the most demanding quantum algorithms poses several
outstanding challenges, including how to control so many qubits simultaneously.
Recently, compact 3D microwave dielectric resonators were proposed as a way to
deliver the magnetic fields for spin qubit control across an entire quantum
chip using only a single microwave source. Although spin resonance of
individual electrons in the globally applied microwave field was demonstrated,
the spins were controlled incoherently. Here we report coherent Rabi
oscillations of single electron spin qubits in a planar SiMOS quantum dot
device using a global magnetic field generated off-chip. The observation of
coherent qubit control driven by a dielectric resonator establishes a credible
pathway to achieving large-scale control in a spin-based quantum computer.
