Nonvolatile operation of vertical ferroelectric gate-all-around nanowire transistors

Ferroelectric gate-all-around (GAA) transistors with a nanowire (NW) channel standing vertically on the substrate would be a potential breakthrough to overcome limitations in the high-integration of ferroelectric memories. In the present study, we fabricated vertical ferroelectric GAA NW transistors (VFGAANWTs) with ZnO NWs (average diameters: 53-193 nm) as the channel, (Hf,Zr)O-2 film (average thicknesses: 9.3-58 nm) as the gate ferroelectric, and Ti as the gate electrode. The channel length was 100-300 nm. The VFGAANWTs showed n-channel operation with on/off ratios of similar to 10, and their on/off states were retained for at least 2 min by the ferroelectric polarization of (Hf,Zr)O-2 after the gate bias was removed, demonstrating the nonvolatile electric field effect in the VFGAANWTs. The results confirm the strong potential of the VFGAANWTs in high-density ferroelectric memory applications.