Determining the Structural Properties of HfO₂ Utilizing Reactive Force Fields

The miniaturization of the MOS transistor and associated infrastructure on chip create the demand for ever thinner gate oxides.Hafnia, HfO₂, satisfies most of the requirements. This work focuses on structural properties of different phases of hafnia utilizing recently developed EAM+QEQ interatomic potentials. Here a combination of classical MD simulations, fist principle MD, high-energy x-ray and neutron diffraction to benchmark the interatomic potentials in the high temperature stable liquid and low-density amorphous solid states of hafnia. Results obtained from computational simulations revealed that an average Hf-O coordination number of about 7 exists in both the liquid and amorphous nanoparticle. The liquid shows a broad distribution of Hf-Hf interactions, while the formation of low-density amorphous nanoclusters can reproduce the sharp split peak in the Hf-Hf partial pair distribution function observed in experiment. The agglomeration of amorphous nanoparticles is associated with the formation of both edge-sharing and corner-sharing of HfO_6,7 which resembles of that observed in the monoclinic phase.