UHV surface chemistry of bis(ethylcyclopentadienyl)ruthenium, (C ₂H₅C₅H₄)₂Ru, on an oxide substrate

The interactions of an organometallic precursor to Ru thin films, bis(ethylcyclopentadienyl)ruthenium, (C₂H₅C ₅H₄)₂Ru, with an amorphous Al₂O ₃ substrate were probed using tools of ultra-high vacuum surface science. The precursor adsorbs and desorbs with no decomposition on Al ₂O₃ that is bare, or covered with patches of O-saturated Ru. In the absence of pre-existing Ru sites, there was no reaction up to 950 K with or without co-dosed O₂ at pressures up to 10_-6 torr. Film-forming reactions do occur under UHV dosing conditions when Ru sites and chemisorbed oxygen are both present. The distribution of chemical states of surface oxygen changes with temperature and influences reaction kinetics and film growth.