STRUCTURE AND OPTICAL-PROPERTIES OF TIN FILMS PREPARED BY DC SPUTTERING AND BY ION-BEAM ASSISTED DEPOSITION

Titanium nitride films have been deposited at 573 K on silicon substrates by dc magnetron sputtering, selecting different bias voltage values, in the 100-800 V range. Additional TiN layers on silicon have been obtained also by ion beam assisted deposition (IBAD) in a machine designed for ion implantation and physical vapour deposition (e-gun). TiN was formed by bombarding at room temperature with a nitrogen ion beam, of energy 30 keV, a growing Ti film, evaporated on silicon in the presence of a nitrogen atmosphere. The films obtained by the two techniques have been characterized with respect to composition, structure, microstructure and optical properties. The effect of ions of different energies impinging on the film during its growth has been found to influence the surface characteristics, among them the optical reflectivity. The importance of process cleanliness is emphasized.