Domain Switching Characteristics in Ga-Doped HfO2 Ferroelectric Thin Films with Low Coercive Field

The gallium-doped hafnium oxide (Ga-HfO₂) films with different Ga doping concentrations were prepared by adjusting the HfO₂/Ga₂O₃ atomic layer deposition cycle ratio for high-speed and low-voltage operation in HfO₂-based ferroelectric memory. The Ga-HfO₂ ferroelectric films reveal a finely modulated coercive field (E_c) from 1.1 (HfO₂/Ga₂O₃ = 32:1) to an exceptionally low 0.6 MV/cm (HfO₂/Ga₂O₃ = 11:1). This modulation arises from the competition between domain nucleation and propagation speed during polarization switching, influenced by the intrinsic domain density and phase dispersion in the film with specific Ga doping concentrations. Higher E_c samples exhibit a nucleation-dominant switching mechanism, while lower E_c samples undergo a transition from a nucleation-dominant to a propagation-dominant reversal mechanism as the electric field increases. This work introduces Ga as a viable dopant for low E_c and offers insights into material design strategies for HfO₂-based ferroelectric memory applications.