Development of a ReaxFF reactive force field for Si/Ge/H systems and application to atomic hydrogen bombardment of Si, Ge, and SiGe (100) surfaces

A new reactive force field was developed for use in molecular dynamics simulations of chemical systems composed of silicon (Si), germanium (Ge), and hydrogen (H) with the ReaxFF code. The development incorporated Ge into the ReaxFF family of reactive potentials by fitting against a diverse training set of DFT data that pertain to Si/Ge/H bonding environments. The predictive capacity of the force field was manifested in molecular dynamics simulations of the H atom bombardment of the (100) surface of c-Si, c-Ge, and c-SiGe crystalline solid slabs in order to simulate the effects of the H-plasma semiconductor cleaning process in the near-surface region. Phenomena related to surface and subsurface H adsorption, H₂ generation, and surface etching were described and compared in relation to material composition and the kinetic energy of the impinging atoms.