MECHANISM OF ION-BEAM-INDUCED DEPOSITION OF GOLD

Ion beam induced deposition is a novel method of thin film growth in w hich adsorbed, metal-bearing molecules are decomposed by incident ener getic ions thus leaving a deposit. In conjunction with finely focused ion beams this process is used in microelectronics for local repair, i .e., deposition of patches of metal film with better than 0.1 mum reso lution. Each ion can decompose as many as 40-50 adsorbed molecules. Th e fundamental aspects of this process, namely how is the energy of the ion transferred to adsorbed molecules over a radius of up to 5 nm, ha ve been studied. The decomposition yield (number of molecules decompos ed/ion) was measured for Ne, Ar, Kr, and Xe ions at 50 and 100 keV. A model based on TRIM calculations was developed. The data correlate wit h this model confirming the view that collision cascades which can pro vide energy to surface atoms over a substantial area are responsible f or ion beam induced deposition.