Differential sputter yields in Si1-x Gex

Sputter yields for ion bombardment of Si1-x Gex alloys are computed using molecular dynamics simulations with the target material modeled using the Stillinger-Weber empirical potential. The results show that Si atoms are preferentially sputtered relative to Ge atoms for all x. The parameters of the Stillinger-Weber potential are altered to investigate the relative importance of atomic mass, bonding energy, atomic number, and atomic density leading to the observed differential sputter yields. The results explain an experimentally observed nonlinear dependence of total sputter yields on composition in Si1-x Gex [Tuboltsev, Phys. Rev. B 72, 205434 (2005)].