Molecular dynamics study on Ar ion bombardment effects in amorphous SiO2 deposition processes

Argon ion bombardment effects on growing amorphous SiO2 films during reactive sputtering deposition processes were examined based on molecular dynamics (MD) and Monte Carlo (MC) simulation techniques. The system we have considered here is a film that is subject to energetic Ar bombardment while it is formed by surface reactions of Si and O atoms separately supplied at low kinetic energies. It has been found that (1) Ar injections preferentially sputter O atoms from the surface over Si and (2) also have a compressing effect on the growing film during the deposition process. In other words, our MD/MC simulations have demonstrated at the atomic level that, with higher energy Ar injections, an amorphous SiO2 film grown in a reactive sputtering deposition process is denser and more Si rich.