Solution processed Li-Al₂O₃/LiNbO₃/Li-Al₂O ₃ stacked gate dielectric for a non-volatile ferroelectric thin film transistor

Lithium niobate (LiNbO3) gate dielectric based SnO2 ferroelectric thin film transistor (FETFT) is fabricated by a simple solution processed technique. However, LiNbO3 alone is not a suitable candidate for a gate insulator of a TFT because of its low band gap. Therefore, Li-Al2O3/LiNbO3/Li-Al2O3 stacked gate dielectric has been used that reduces the gate leakage current by an order of magnitude compared to the LiNbO3 only device. Moreover, ionic polarization of Li-Al2O3 thin films that originated from mobile Li+ of Li-Al2O3, compensate for the ferroelectric charge polarization of LiNbO3 film. By reducing gate leakage current and compensating ferroelectric charge polarization, it becomes possible to achieve ferroelectric memory retention up to 7.2x 10(3) s of time with a difference of ON/OFF state by 3 times whereas the reference LiNbO3 device almost merges to each other very quickly. Besides, these ferroelectric TFTs (FETFT) can operate within 2 V operating voltage due to the strong ionic polarization of the gate dielectric. The carrier mobility of 1.9 cm(2). V-1.s(-1), current ON/OFF ratio of 1.6 circle plus 10(4) and subthreshold swing (SS) of 167 mV.decade(-1) has been achieved under 2 V operation of this FETFT, whereas memory retention time has been studied at 0 V gate and 1 V drain bias. (c) 2023 Elsevier B.V. All rights reserved.