Atomistic analysis of Ge on amorphous SiO2 using an empirical interatomic potential

The fidelity of a Tersoff-based empirical potential model for the Ge–Si–O ternary atomic system is studied in detail, with the ultimate aim of validating the potential for later use in large-scale simulations of Ge selective epitaxial growth. Several comparisons are presented between the predictions of atomistic simulations based on the empirical potential studied here and prior experimental measurements and electronic structure calculations. The points of comparison include the structure and thermodynamics of bulk amorphous silica (a-SiO2), the a-SiO2 free surface, the c-Si/a-SiO2 interface, the c-Ge/a-SiO2 interface, and the desorption, wetting, and diffusion behavior of Ge atoms on a-SiO2 surfaces. A single fitting parameter, which describes the strength of the Ge–O interaction, is used to establish good agreement between the empirical potential predictions and experimental measurements across all points of comparison. We conclude that a Tersoff-based empirical potential, while it neglects explicit Coulombic interactions and is highly simplified, is a reasonable basis for probing certain features of the Ge/SiO2/Si material system.