Effects of surface structures of MgO(100) single crystal substrates on ferroelectric PbTiO₃ thin films grown by radio frequency sputtering

Effects of surface structures of MgO(100) single crystal substrates on the growth of PbTiO₃ thin films by radio frequency magnetron sputtering have been investigated. First, the surface structures of the substrates prepared by cleaving, polishing, and annealing were characterized using Rutherford backscattering spectroscopy combined with channeling, surface sensitive x‐ray scattering, and atomic force microscopy. We found a strong correlation between the surface structures and the growth of the thin films. The film on the cleaved substrate was not uniform and its crystallinity was poorer than that on the polished or the annealed substrates due to the presence of large cleavage steps, whereas better epitaxiality was found on the annealed substrate than on the polished substrate. Favorable effects of thermal annealing after polishing have been explained based on surface step rearrangements, damage removal, and improvement in surface flatness by the thermal annealing treatment.