Kinetics of anatase phase formation in TiO2 films during atomic layer deposition and post-deposition annealing

Anatase phase formation in TiO2 films obtained by atomic layer deposition (ALD) is investigated. At growth temperature close to 200 degrees C, the anatase phase of TiO2 originates from crystalline seeds formed in an amorphous layer. These seeds, formed in the initial stages of a film growth, allow an expansion of the anatase phase in the amorphous parts and their transformation. This expansion occurs either during a further growth process or during a post-deposition annealing at relatively low temperatures (160-220 degrees C). The process of a lateral expansion of the anatase phase within the amorphous one was found to be thermally activated with an activation energy of 1.5 eV.