Fully Transparent Non‐volatile Memory Thin‐Film Transistors Using an Organic Ferroelectric and Oxide Semiconductor Below 200 °C

Abstract 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 Al₂O₃ 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 1.8 V 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 V decade⁻¹, 10⁸, and 10⁻¹³ A, respectively. All these characteristics correspond to the best performances among all types of non‐volatile memory transistors reported so far, although the programming speed and retention time should be more improved.