Non-volatile Thin Film Transistors Using Ferroelectric/ITO Structures

摘要

We report ferroelectric-gate thin film transistors (TFTs) using indium tin oxide (ITO) as a channel material. Bottom-gate structure TFTs have been fabricated using ferroelectric Pb(Zr,Ti)O_3 (PZT) film as a gate insulator and ITO channel. Ferroelectric and ITO layers were formed by the sol-gel technique and RF sputtering, respectively. Drain current-drain voltage (I_D-V_D) characteristics of PZT/TTO ferroelectric-gate TFTs exhibit typical n-channel transistor operations with clear current saturation and electrical properties were improved by the post annealing. Drain current-gate voltage (I_D-V_G) characteristics demonstrate clear counterclockwise hysteresis loop due to the ferroelectric gate insulator. The obtained memory window is 2V. The on/off current ratio of more than 10~2 has been obtained, which indicates that the ITO channel is sufficiently depleted by the ferroelectric polarization.