Carrier scattering induced by thickness fluctuation of silicon-on-insulator film in ultrathin-body metal–oxide–semiconductor field-effect transistors

Abstract

We demonstrate that carrier scattering induced by the thickness fluctuation of a silicon-on-insulator (SOI) film reduces electron mobility in ultrathin-body metal–oxide–semiconductor field-effect transistors with SOI thickness, $T_{\mathrm{SOI}},$ of less than 4 nm at room temperature and is the dominant scattering mechanism at low temperatures. The thickness fluctuation of a nanoscaled SOI film induces large potential variations due to the difference of quantum-confinement effects from one part to another, and thus carrier scattering potentials are formed in the channel. It is shown that experimental electron mobility follows the theoretical $T_{\mathrm{SOI}}$ dependence and the expected temperature dependence of the scattering induced by SOI thickness fluctuation.