  The strong spin-orbit coupling in hole spin qubits enables fast and
electrically tunable gates, but at the same time enhances the susceptibility of
the qubit to charge noise. Suppressing this noise is a significant challenge in
semiconductor quantum computing. Here, we show theoretically that hole Si
FinFETs are not only very compatible with modern CMOS technology, but they
present operational sweet spots where the charge noise is completely removed.
The presence of these sweet spots is a result of the interplay between the
anisotropy of the material and the triangular shape of the FinFET
cross-section, and it does not require an extreme fine-tuning of the
electrostatics of the device. We present how the sweet spots appear in FinFETs
grown along different crystallographic axes and we study in detail how the
behaviour of these devices change when the cross-section area and aspect ratio
are varied. We identify designs that maximize the qubit performance and could
pave the way towards a scalable spin-based quantum computer.
