Oxide Semiconductor-Based Organic/Inorganic Hybrid Dual-Gate Nonvolatile Memory Thin-Film Transistor

An organic/inorganic hybrid dual-gate (DG) nonvolatile memory thin-film transistor (M-TFT) was proposed as a device with high potential for implementing large-area electronics on flexible and/or transparent substrates. The active channel and bottom and top gate insulators (GIs) of the M-TFT were composed of In-Ga-Zn-O, Al₂O₃, and poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)], respectively. It was confirmed that the fabricated DG M-TFT showed excellent device characteristics, in which the obtained field-effect mobility, subthreshold swing, and on/off ratio were approximately 32.1 cm² V^-1 s^-1, 0.13 V/dec, and 10⁸, respectively. It was also successfully demonstrated that the DG configuration for the proposed M-TFT could effectively work for improving the device controllability by individually controlling the bias conditions of the top gate and bottom gate (BG). The turn-on voltage could be dynamically modulated and controlled when an appropriate fixed negative voltage was applied to the BG. The required duration of the programming pulse to obtain a memory margin of more than 10 could be reduced to 100 μs. These results correspond to the first demonstration of a hybrid-type DG M-TFT using a ferroelectric copolymer GI/oxide semiconducting active channel structure and demonstrate the feasibility of a promising memory device embeddable in a large-area electronic system.