  As CMOS structures are envisioned to host silicon spin qubits, and for
co-integrating quantum systems with their classical control blocks, the
cryogenic behaviour of such structures need to be investigated. In this paper
we characterize the electrical properties of Gate-All-Around (GAA) n-MOSFETs Si
nanowires (NWs) from room temperature down to 1.7 K. We demonstrate that those
devices can operate both as transistor and host quantum dots at cryogenic
temperature. In the classical regime of the transistor we show improved
performances of the devices and in the quantum regime we show systematic
quantum dots formation in GAA devices.
