On the origin of tunneling barriers in silicon single electron and single hole transistors

To clarify the channel potential profiles, Coulomb blockades of single electron and single hole tunneling in Si nanosize narrow channel metal-oxide-semiconductor field-effect transistors are intensively studied. Devices with both n⁺ and p⁺ source/drain contacts were fabricated on silicon-on-insulator substrates. Transport properties of a hole system as well as an electron system induced in the same channel were investigated. It is found from the experimental results that potential fluctuations in the channel act as tunnel barriers for both electrons and holes. Lateral quantum confinement effects or silicon oxide (SiO_x) are thought to be the cause of tunnel barriers.