Effects of dimensional scaling on the electronic transport properties of silicon nanofilms and nanowires

A detailed investigation focused upon evaluating the effects of dimensional cross-sectional nanoscaling of silicon features on the electronic transport properties is presented. The feature dimensions ranged from ∼200 nm down to ∼10 nm. This range represents transition region from bulk properties towards the onset of quantization. The structures were fabricated on silicon-on-insulator using interferometric lithography, reactive-ion-etching and thermal oxidation methods. In order to investigate the optical and electronic properties, the nanostructures were configured in a two terminal test device configuration. Characterization methods included; dark and illuminated steady-state DC measurements and optically pulsed transient time response measurements using a modified version of the Haynes-Shockley experiment for evaluating the carrier mobility as a function of scaling the feature cross-section. Results showed that the total carrier drift-diffusion dependent conduction increases as the feature cross-sectional dimensions are reduced from ∼200 nm to ∼10 nm due to carrier confinement effects and clear differences between 1D (nanofilms) versus 2D (nanowires) scaling effects are observed.