Kh. Chae et al., DYNAMIC MONTE-CARLO SIMULATION FOR THE ION-BEAM-INDUCED ATOMIC TRANSPORT IN BILAYER SYSTEMS, Journal of the Korean Physical Society, 26(6), 1993, pp. 622-627
A dynamic Monte-Carlo simulation (MCS) program, containing not only co
llisional mixing but also sputtering effects, has been developed to el
ucidate the dynamic mixing processes and the atomic transport of const
ituents in Al-Pd bilayer systems. MCS results reveal that the preferen
tial inward displacement of the top-layer element dominates and that t
here is an enhancement of the inward displacement when the heavier ele
ment is in the top layer. Also we develop an analytical model to inter
pret this MCS result. The inward displacement is controlled by both of
an anisotropic and an isotropic atomic transport. The anisotropic ter
m is caused by the primary recoil of atoms, which has a characteristic
phi (ion dose) dependence, and the isotropic term is associated with
the random cascade motion, which has a square-root phi dependence. How
ever, the outward displacement is governed by only the isotropic motio
n; thus, the inward displacement always dominates over the outward mot
ion, which leads to a preferential displacement of the top-layer eleme
nt to the bottom layer.