Fully transparent non-volatile memory thin-film transistors using an organic ferroelectric and oxide semiconductor below 2000c

A fully transparent non-volatile memory thin-film transistor (T-MTFT) is demonstrated. The gate stack is composed of organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and oxide semiconducting Al-Zn-Sn-O (AZTO) layers, in which thin Al₂O ₃ is introduced between two layers. All the fabrication processes are performed below 200°C on the glass substrate. The transmittance of the fabricated device was more than 90% at the wavelength of 550 nm. The memory window obtained in the T-MTFT was 7.5 V with a gate voltage sweep of-10 to 10 V, and it was still 1.8V even with a lower voltage sweep of -6 to 6 V. The field-effect mobility, subthreshold swing, on/off ratio, and gate leakage currents were obtained to be 32.2 cm² V^-1 s ^-1,0.45 Vdecade^-1,10⁸, and 10^-13 A, respectively. All these characteristics correspond to the best performances among all types of nonvolatile memory transistors reported so far, although the programming speed and retention time should be more improved.