Domain Switching Characteristics in Ga-Doped HfO 2 Ferroelectric Thin Films with Low Coercive Field.

The gallium-doped hafnium oxide (Ga-HfO 2 ) films with different Ga doping concentrations were prepared by adjusting the HfO 2 /Ga 2 O 3 atomic layer deposition cycle ratio for high-speed and low-voltage operation in HfO 2 -based ferroelectric memory. The Ga-HfO 2 ferroelectric films reveal a finely modulated coercive field ( E c ) from 1.1 (HfO 2 /Ga 2 O 3 = 32:1) to an exceptionally low 0.6 MV/cm (HfO 2 /Ga 2 O 3 = 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 HfO 2 -based ferroelectric memory applications.