Amorphous IGZO nonvolatile memory thin film transistors using Ta ₂O ₅ gate dielectric

A nonvolatile memory thin-film transistor (MTFT) using an amorphous indium gallium zinc oxide (a-IGZO) semiconducting channel and a Ta ₂O ₅ gate insulator is proposed. The high-dielectric-constant material Ta ₂Oi was deposited by e-beaming and used for the charge storage layer, i.e., a metal-oxide-semiconductor (MOS) capacitor. We obtained memory windows (δVth = 2 V) at 3-V gate voltage and realized reliable memory operations. Therefore, a-IGZO TFT with Ta ₂Oi can be employed in integrated high-performance nonvolatile memory devices for applications to transparent displays and flexible electronic devices.