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-nm-thick poly-4-vinylphenol (PVP) and 200-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 0.36cm2∕V and a large memory hysteresis in the transfer characteristics due to the ferroelectric P(VDF/TrFE). The retention of the device lasted over 2h.

Optimization of a Solution-Processed SiO2 Gate Insulator by Plasma Treatment for Zinc Oxide Thin Film Transistors

“…1(b). CAPS, OCAPS, OPS and OAPS films were formed onto pre-patterned Al gate electrodes [14][15][16][17] μm, respectively.…”

Ferroelectric Copolymer-Based Plastic Memory Transistors

“…A powerful alternative for enhancing and stabilizing the device performance is to utilize the oxide semiconductor such as ZnO and IGZO, which is one of the most important features of our proposed plastic memory transistor. The oxide semiconductor-based TFTs present such beneficial features as high field-effect mobility, excellent uniformity, and robust device stability (Hoshino K. et al, 2009;Jeong J. K. et al, 2008;Nomura et al, 2004). As results, the oxide TFTs have attracted huge interest as one of the most promising backplane device technologies for the next-generation liquid-crystal display (LCD) (Osada T. et al, 2010) or organic light-emitting diode display (OLED) (Ohara H. et al, 2010;Park J. S. et al, 2009) with a large size and a high resolution.…”

“…The first one is that the memory device reliabilities, especially data retention, were not so satisfying at this stage. The typical retention times of the previously reported memory TFT employing the polymeric ferroelectric GI and oxide channel are still in the range of several hours even when they were fabricated on the glass substrate (Lee K. H. et al, 2009a;Noh S. H. et al, 2007;Park C. H. et al, 2009). Three significant factors that critically affect the retention behaviors are intrinsic depolarization field, gate leakage components, and interface quality.…”

Adsorbate/absorbate interactions with organic ferroelectric polymers

“…As the copolymer poly(vinylidene fluoride with trifluoroethylene) is ferroelectric, transistors, both fully organic heterojunctions [82][83][84][85][86][87][88][89][90][91][92][93][94] and hybrid heterojunctions with an inorganic semiconductor [95][96][97][98][99], exhibit gate voltage dependent hysteresis, indicating the potential of P(VDF-TrFE) copolymers for nonvolatile random access memory devices. An example of this type of gate voltage dependent hysteresis for an organic heterojunction transistor fabricated with polyaniline as a p-layer [69,70] on top of P(VDF-TrFE 70:30) where the latter is the gate dielectric layer is illustrated in Figure 15.…”