Molecular dynamics results using an improved Tersoff-Brenner style interatomic potential for Si-F (denoted by TB-HG) are presented. In simulations of F/Ar+, F+, and SiF3+ etching of silicon, the TB-HG potential predicts different behaviour from that of Stillinger and Weber (SW). With the SW potential, F atoms do not mix into Si surfaces, creating instead a roughened surface with F on the outside. With the TB-HG potential, F atoms are able to mix into Si, leading to higher F uptake and Si etch rate in all cases. The TB-HG potential is compared to the modified SW potential of Weakliem et al (SW-WWC) in simulations of F+ etching of Si. The quantitative values of steady-state F uptake and Si etch rate for the (SW-WWC and TB-HG) potentials are nearly identical, but surface structure and etch product distributions are qualitatively different. Evidence of spurious energetic barriers in the SW potential form is given.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics