Dynamic analysis of non-linear wake-up behavior in Hf0.7Zr0.3O2 thin film

Abstract

We report on the nonlinear wake-up behavior against the external electric field cycling in the ferroelectric Hf0.7Zr0.3O2 thin film. Two distinct scaling regimes during the increase of the remnant polarization with different activation energies were observed in TiN/Hf0.7Zr0.3O2/TiN cells. The transmission electron microscopy revealed the structural phase transition from the monoclinic structure to the orthorhombic structure of the Hf0.7Zr0.3O2 film after the wake-up behavior. During the phase change, as the remnant polarization enhanced, the dielectric constant of the Hf0.7Zr0.3O2 film increased with the external field cycling. The temperature dependence of the wake-up behavior revealed that each estimated activation energies for the early and later enhancement of the remnant polarization are 1.12 eV and 0.73 eV, respectively. First principle calculations show that the oxygen vacancies can reduce the activation energy barrier for the structural phase transition.