Polymeric gate dielectric interlayer of cross-linkable poly(styrene-r-methylmethacrylate) copolymer for ferroelectric PVDF-TrFE field effect transistor memory

Abstract

A new polymeric gate dielectric interlayer of a cross-linkable poly(styrene-random-methylmethacrylate) copolymer is introduced with a good thermal and chemical resistance in bottom gate Ferroelectric Field Effect Transistor (FeFET) memory with pentacene active layer and ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) one. A thin uniform PVDF-TrFE film was successfully formed with well defined ferroelectric microdomains on an interlayer. Thickness of the interlayer turns out to be one of the most important factors for controlling gate leakage current which is supposed to be minimized for high ON/OFF bistability of a FeFET memory. An interlayer inserted between gate electrode and PVDF-TrFE layer significantly reduces gate leakage current, leading to source-drain OFF current of approximately 10(-11) A in particular when its thickness becomes greater than approximately 25 rim. A reliable FeFET device shows a clockwise I-V hysteresis with drain current bistablility of 10(3) at +/- 40 V gate voltage. (C) 2009 Elsevier B.V. All rights reserved