The influence of deposition parameters on the structure and properties of magnetron-sputtered titania coatings

TiO2 films are widely used as high refractive index dielectric layers in multi-layer optical devices and functional films. The optical properties of titania films, and their stability, are critically dependent on the film structure, which in turn, is dependent on the deposition conditions used. Titania can exist in three forms: amorphous, anatase and rutile. Titania films were grown by reactive pulsed magnetron sputtering under systematically controlled conditions using dual variable field strength planar magnetrons. The effects of deposition conditions, including the degree of unbalance of the magnetrons and pulse frequency, on titania films were investigated. The influence of these process variables was determined in terms of their impact on both deposition rate and process stability. Film properties were analyzed in terms of structure, crystallinity and refractive index. Results to date are discussed here.