Fundamental Properties of Ferroelectric and Anti-Ferroelectric Hafnium Zirconium Oxides: Scaling Limit, Switching Speed and Polarization Density

Abstract

The ferroelectric (FE) and anti-ferroelectric (AFE) properties of hafnium zirconium oxide (HZO) are investigated systematically down to 3 nm. The ferroelectric polarization, switching speed and the impact of metal electrodes, such as atomic layer deposited (ALD) TiN and WN versus sputtered W, are studied. Record high remnant polarization (P r ) on FE HZO and record high saturation polarization (PS) on AFE HZO are achieved with WN electrodes, especially in ultrathin sub-10 nm regime. [1, 2] A high dielectric constant of 30.4 is achieved on AFE HZO. The polarization switching speeds of FE and AFE HZO are also systematically studied. For the first time, it is found polarization switching speed is faster in AFE HZO than FE HZO. Record fast sub- nanosecond single pulse polarization switch is achieved on FE HZO for the first time, [3] The work is supported by DARPA/SRC JUMP ASCENT Center.