Structure and Dielectric Properties of Amorphous High-kappa Oxides: HfO2, ZrO2 and their alloys

TL;DR

This study combines molecular dynamics and quantum mechanical calculations to investigate the structural and dielectric properties of amorphous high-kappa metal oxides HfO2, ZrO2, and their alloys, aligning well with experimental data.

Contribution

It introduces a combined MD and DFT approach to model amorphous high-kappa oxides and accurately predicts their dielectric constants.

Findings

Coordination numbers match experimental data.

Calculated dielectric constants agree with experiments.

Values are close to cubic phase dielectric constants.

Abstract

High-$\kappa$ metal oxides are a class of materials playing an increasingly important role in modern device physics and technology. Here we report theoretical investigations of the properties of structural and lattice dielectric constants of bulk amorphous metal oxides by a combined approach of classical molecular dynamics (MD) - for structure evolution, and quantum mechanical first principles density function theory (DFT) - for electronic structure analysis. Using classical MD based on the Born-Mayer-Buckingham potential function within a melt and quench scheme, amorphous structures of high-$\kappa$ metal oxides Hf$_{1-x}$Zr$_x$O$_2$ with different values of the concentration $x$, are generated. The coordination numbers and the radial distribution functions of the structures are in good agreement with the corresponding experimental data. We then calculate the lattice dielectric constants of the materials from quantum mechanical first principles, and the values averaged over an ensemble of samples agree well with the available experimental data, and are very close to the dielectric constants of their cubic form.