ELEMENTARY PROCESSES IN THIN-FILM FORMATION STIMULATED BY HIGH-ENERGYION IRRADIATION

The elementary processes (such as adsorption from residual gases, deso rption, sputtering, redistribution of the film and substrate atoms) oc curring during ion beam activated growth of a metallic film on a semic onductor substrate are considered in the proposed phenomenological mod el. The probabilities of the above processes are included in an equati on of balance describing the ith sort atoms concentration variation in the first monolayer. Ion activated adsorption is treated for the inte raction of oxygen atoms with ion activated surface atoms. It is assume d that activation of atoms is only in the first monolayer, arising fro m energy transfer from incident ions to atoms in the first monolayer. The Ag-Si interface adsorbed oxygen amount (from residual gases) for e xperimental dependences on the Ar+, Ne+, He+ ion energy (50-175 keV) a nd ion flux density were extrapolated using the phenomenological model . It was shown that at ion flux densities below 10(12) cm-2 s-1 adsorp tion dominates strongly. The increase of the amount of activated atoms with the electronic energy deposition growth allows the conclusion th at electronic energy losses are essential in the process of ion activa ted oxygen adsorption and the ion activated atoms may be interpreted a s the atoms with excited extranuclear electrons. According to the calc ulations, ion activated adsorption is expected if the ratio of ion and oxygen flux densities is less than 0.025.