Mass transport in ion–nanostructure interactions

Abstract

Recently, interesting differences for ion–uniform film and ion–nanostructure interaction phenomena, particularly relating to ion beam mixing effects have been reported. Upon irradiation with 1.5MeV Au2+ ions on isolated Au nanostructures on silicon substrate, a higher probability of crater formation, larger sputtered particle size and its coverage and enhanced sputtering yield compared to the continuous films of Au on Si substrate were observed. Ion bombardment at high flux (≈6.3×1012ionscm−2s−1) showed a dramatic mass transport from nanostructures extending up to a distance of about 60nm into the substrate, much beyond their size. In this paper, RBS/Channeling results would be presented to elucidate on the arrangement of re-distributed gold atoms location in silicon and silicide matrix. Scanning transmission electron microscopy (STEM, with high angle annular dark field imaging) was used to complement the RBS results in determining the unusual mass transport and under ion–nanostructure interaction. The amorphous nature of the silicon matrix, that is deduced from both the RBS/Channeling and from TEM measurements, is an important factor in enhanced diffusion process resulting in dramatic mass flow.