Flux dependent MeV ion induced modification of nano-Ag/Si system

Thin films of Ag (1.5 nm thick) are grown on Si (1 1 1) substrates using evaporation method in high vacuum condition and due to non-wetting nature of silver, isolated islands of mean size ≈12.0 nm have been formed on the surface. Au2+ (1.5 MeV) ions have been used to irradiate the above systems at various fluences (5 × 1013-1 × 1015 cm−2) at an impact angle of 5° and at a flux of 6.3 × 1012 cm−2 s−1 (corresponding to a beam current density of 2.0 μA cm−2 for Au2+ ions). Ion beam induced embedding is observed to begin at a fluence of 1 × 1014 cm−2 for this high flux whereas low flux irradiations (current density ≈ 0.02 μA cm−2) of Au2+ ions under similar irradiation conditions did not yield embedding (impact angle 5°). High resolution transmission electron microscopy measurement showed no mixing in the form of silicide formation. These results are compared with high flux modifications in Au/Si system.