The interface and the field effect in thin-film transistors

Abstract

The effects of interface properties on the performance of thin-film transistors are examined theoretically. The static characteristics, e.g., the off conductance and the on-off ratio, and the dynamic response represented by the fraction of induced charge that is free, are considered. The interfaces, both at the gate side and the substrate side, are specified by the interface charge transfer (at equilibrium) from the semiconductor to the insulator, as well as the more familiar density of interface states. The properties of the two interfaces are found to control different regimes (high field and low field) of field-effect conductance. Thus, by a careful tailoring of the two interfaces, and/or the two insulator materials, the transistor characteristics can be optimized.