Ferroelectric and Anti-Ferroelectric Hafnium Zirconium Oxide: Scaling Limit, Switching Speed and Record High Polarization Density

摘要

The ferroelectric (FE) and anti-ferroelectric (AFE) properties of hafuium zirconium oxide (HZO) are investigated systematically down to 3 nm. The ferroelectric polarization, switching speed and the impact of atomic layer deposited (ALD) tungsten nitride (WN) electrodes are studied. Record high remnant polarization (Pr), on FE HZO and record high saturation polarization (Ps) on AFE HZO are achieved with WN electrodes, especially in ultrathin sub-10 nm regime. A high dielectric constant of 30.4 is achieved on AFE HZO. The polarization switching speed of FE and AFE HZO, associated with C-V frequency dispersion, are also studied. For the first time, it is found polarization switching speed is faster in AFE HZO than FE HZO, suggesting AFE-FET could be more promising for high speed memory devices.