Orientation selection in thin platinum films on (001) MgO

Orientation selection in platinum films of ∼20 nm thickness deposited onto (001) MgO substrates by e-beam evaporation was investigated through ion beam channeling and x-ray diffraction. A mixture of crystallites having (111) and (001) orientation was observed in Pt films deposited over a range of substrate temperatures from 25 to 700 °C, with the (111) orientation dominant at low temperatures. The (111) orientation was present in these evaporated films at significantly higher substrate temperatures than reported for Pt films deposited by sputtering or pulsed laser deposition. Both orientations had strongly preferred in-plane orientations: [110] Pt//[110] MgO for the (001)-oriented crystallites and [110]Pt//[110] MgO for the (111). The orientation selection process was rationalized based on the expected relative interfacial energies for these two orientations.