Highly oriented Nb-doped lead titanate thin films by reactive sputtering: Fabrication and structure analyses

Highly oriented lead titanate thin films have been deposited on bare (100)MgO substrates and on (100)Pt/(100)MgO substrates by reactive sputtering. By adding metallic niobium chips to the target. Nb-doped PbTiO3 films could be obtained as well. The variation in the orientation of PbTiO3 films due to the deposition conditions is described in detail. Due to the highly oriented nature of the films, two types of X-ray diffraction methods were used to evaluate the effect of Nb doping on the tetragonality ratio c/a: one was the conventional theta-2 theta Bragg-Brentano X-ray diffraction method (XRD), the other was the in-plane energy-dispersive total reflection X-ray diffraction method (ED-TXRD), which could provide the lattice vectors perpendicular (c axis) and parallel (a axis) to the substrate, respectively. Furthermore, the epitaxy of the deposited PbTiO3 films in relation to the (100)-cut MgO single crystal substrate could be confirmed using ED-TXRD.