  An ultra-small Coulomb blockade device can be regarded as a mesoscopic
artificial atom system and provides a rich experimental environment for
studying quantum transport phenomena[1]. Previously, these quantum effects have
been investigated using relatively large devices at ultra-low temperatures,
where they give rise to a fine additional structure on the Coulomb oscillations
[2-13]. Here, we report transport measurements carried out on a sub-2nm
single-electron device; this size is sufficiently small that Coulomb blockade,
and other quantum effects, persist up to room temperature (RT). These devices
were made by scaling the size of a FinFET structure down to an ultimate
limiting form, resulting in the reliable formation of a sub-2nm silicon Coulomb
island. Four clear Coulomb diamonds can be observed at RT and the 2nd Coulomb
diamond is unusually large, due to quantum confinement. The observed
characteristics are successfully modeled on the basis of a very low electron
number on the island, combined with Pauli spin exclusion. These effects offer
additional functionality for future RT-operating single-electron device
applications
