Reactive Ar ion beam sputter deposition of TiO2 films: Influence of process parameters on film properties

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2017-03, Vol.395, p.17-23
• Main Authors: Bundesmann, C., Lautenschläger, T., Thelander, E., Spemann, D.
• Format: Article
• Language: English
• Subjects: Composition; Ion beam sputter deposition; Ion-solid interaction; Mass density; Optical properties; TiO2
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2017.01.078

•Ion beam sputter deposition under systematic variation of process parameters.•Thickness, growth rate, structure, mass density, composition, optical properties.•All TiO2 films are amorphous with systematic variations in mass density.•Considerable amount of inert process gas correlated with scattering angle.•Correlation of mass density and index of refraction. Several sets of TiO2 films were grown by Ar ion beam sputter deposition under systematic variation of ion energy and geometrical parameters (ion incidence angle and polar emission angle). The films were characterized concerning thickness, growth rate, structural properties, composition, mass density, and optical properties. The film thicknesses show a cosine-like angular distribution, and the growth rates were found to increase with increasing ion incidence angle and ion energy. All films are amorphous and stoichiometric, but can contain a considerable amount of backscattered primary particles. The atomic fraction of Ar particles decreases systematically with increasing scattering angle, independent from ion energy and ion incidence angle. Mass density and index of refraction show similar systematic variations with ion energy and geometrical parameters. The film properties are mainly influenced by the scattering geometry, and only slightly by ion energy and ion incidence angle. The variations in the film properties are tentatively assigned to changes in the angular and energy distribution of the sputtered target particles and back-scattered primary particles.