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, TSOI, 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 TSOI dependence and the expected temperature dependence of the scattering induced by SOI thickness fluctuation.