Quantum confinement induced performance enhancement in sub-5-nm lithographic Si nanowire transistors.

We demonstrate lithographically fabricated Si nanowire field effect transistors (FETs) with long Si nanowires of tiny cross sectional size (∼3-5 nm) exhibiting high performance without employing complementarily doped junctions or high channel doping. These nanowire FETs show high peak hole mobility (as high as over 1200 cm(2)/(V s)), current density, and drive current as well as low drain leakage current and high on/off ratio. Comparison of nanowire FETs with nanobelt FETs shows enhanced performance is a result of significant quantum confinement in these 3-5 nm wires. This study suggests simple (no additional doping) FETs using tiny top-down nanowires can deliver high performance for potential impact on both CMOS scaling and emerging applications such as biosensing.