Zno field-effect transistors with leadzirconate-titanate ferroelectric gate

Ferroelectric lead-zirconate-titanate [Pb(Zr_0·53Ti_0·47)O₃] thin films with remnant polarisation and large dielectric constant have been employed in non-volatile field-effect transistor memories as gate dielectrics. Oxide semiconductor-zinc oxide (ZnO) is introduced as the channel layer because of its low crystallization temperature, good integration with different materials and low costs. In this paper, field-effect transistors using ZnO as the channel and lead-zirconate-titanate as the gate dielectric have been fabricated and characterised. Lead-zirconate-titanate and ZnO films were deposited by Sol-Gel and radio frequency (RF)-sputtering methods, respectively. Typical n-channel properties with clear current saturation in drain current v. drain voltage (I_ds- V_ds) characteristics have been obtained. The transfer characteristics (source-drain current v. gate voltage, I_ds-V_gs) exhibited a significantly hysteresis behaviour because of the ferroelectric polarisation properties of the lead-zirconate-titanate gate dielectric. The characteristics of ferroelectric layer inducing channel electron transport properties modulation and hysteresis behaviours in ZnO-lead-zirconate-titanate structured field-effect transistors can be used for future non-volatile memory applications.