Silicon single-electron tunneling device fabricated in an undulated ultrathin silicon-on-insulator film

Abstract

We report on a silicon single-electron tunneling device fabricated in an ultrathin (∼3 nm) silicon-on-insulator (SOI) film whose surface is undulated by an alkaline-based solution. The nanometer-scaled undulation in the ultrathin film results in great SOI thickness variations and brings about large electron-potential fluctuations, due to the difference of the quantum confinement effects from one part to another. Consequently, a number of quantum dots are effectively formed in the undulated ultrathin SOI film. This device shows clear Coulomb blockade oscillations at 80 K, as well as nonvolatile single-electron memory functions even at room temperature. The measurements of the undulation with atomic force microscopy reveal that the undulation has two correlation lengths. Based on the analysis of electrical characteristics, it is concluded that the Coulomb blockade oscillations are dominated by a quantum dot formed by the longer-correlation-length undulation and that single-electron memory effects are due to quantum dots formed by the shorter-correlation-length undulation.