Gas-Phase Electron-Impact Activation of Atomic Layer Deposition (ALD) Precursors: MeCpPtMe₃

The use of gas-phase electron-impact activation of metalorganic complexes to facilitate atomic layer depositions (ALD) was tested for the case of (methylcyclopentadienyl)Pt(IV) trimethyl (MeCpPtMe₃) on silicon oxide films. Uptake enhancements of more than 1 order of magnitude were calculated from X-ray photoelectron spectroscopy (XPS) data. On the basis of the measured C:Pt ratios, the surface species were estimated to mainly consist of MeCpPt moieties, likely because of the prevalent formation of [MeCpPtMe_x-nH]⁺ ions after gas-phase ionization (as determined by mass spectrometry). Counterintuitively, more extensive adsorption was observed on thick SiO₂ films than on the native thin SiO₂ film that forms on Si(100) wafers, despite the former having virtually no surface OH groups. The adsorption of MeCpPt fragments on silicon oxide surfaces was determined by density functional theory (DFT) calculations to be highly exothermic and to favor attachment to Si-O-Si bridge sites.