Tunneling barrier structures in room-temperature operating silicon single-electron and single-hole transistors

We investigate the tunneling barrier structures formed in the room-temperature-operating silicon single-electron transistors and single-hole transistors. The devices are in the form of ultranarrow-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) with both n(+) and p(+) source/drain contacts. From the Coulomb blockade characteristics of both electrons and holes in the same physical channel profile, it is found that higher tunneling barriers and smaller, effective dots (potential wells) which cannot be physically defined are formed in the valence band than in the conduction band. It is suggested that, in order to improve the operation temperature of single charge devices, a single-hole system is preferable to a single-electron system.