In situ epitaxial growth of lead zirconate titanate films by bias sputtering at high RF power

High-quality epitaxial lead zirconate titanate (PZT) films with high growth rate were successfully grown by bias sputtering on (001) MgO single crystal substrates using a composite ceramic target. The composite ceramic target composed of a PbO pellet on the center of Pb-1.2(Zr0.4Ti0.6)O-3 ceramics was necessary to stably obtain perovskite-phase PZT films under high RF power by sputtering. At high RF power, the application of DC bias voltages to the growing PZT films increased the growth rate and changed the Ti/Zr composition. In particular, the optimum negative bias voltage considerably improved the crystallinity and surface morphology of the films compared with the conventional sputtering process. The optimum negative bias voltage plays a role in suppressing the bombardments of the energetic negative oxygen ions on growing films and also in making low-energy positive ions assist help in crystallization.