ZnO-based nonvolatile memory thin-film transistors with polymer dielectric/ferroelectric double gate insulators

Abstract

The authors report on the fabrication of a top-gate ZnO thin-film transistor (TFT) with a polymer dielectric/ferroelectric double-layer gate insulator that was formed on patterned ZnO through a sequential spin-casting process of $450\text{-}\mathrm{nm}$ -thick poly-4-vinylphenol (PVP) and $200\text{-}\mathrm{nm}$ -thick poly(vinylidene fluoride/trifluoroethylene) [P(VDF/TrFE)]. Compared to the single P(VDF/TrFE) layer, double layer shows remarkably reduced leakage current with the aid of the PVP buffer. TFT with the PVP/P(VDF/TrFE) double layer exhibits a field effect mobility of $0.36{\mathrm{cm}}^2∕\mathrm{V}$ and a large memory hysteresis in the transfer characteristics due to the ferroelectric P(VDF/TrFE). The retention of the device lasted over $2\mathrm{h}$ .