FORMATION OF THE SECONDARY PHASES IN THE PB-CONTAINING PEROVSKITE FILMS BY PULSED-LASER DEPOSITION

The growth behavior of Pb2+-containing ferroelectric thin films has be en systematically examined. The kinetics of the formation of perovskit e phase were successfully enhanced by using a material containing no Z r4+-ions, viz., Pb0.95La0.05Ti0.9875O3 (PLT) films, and by utilizing p latinum coating on silicon substrate. Meanwhile, the formation of TiO2 phase (rutile) on PLT/Pt(Si) films has been observed and was ascribed to both the outward diffusion of Ti4+-ions from the Ti-layer undernea th the Pt-coating and the loss of Pb2+-ions on the surface of the film s. The perovskite materials, which were free of either pyrochlore, Zr- rich phase, or TiO2 phase, can be obtained by in situ depositing the P LT films at 450-degrees-C substrate temperature and 1 mbar oxygen pres sure. Thus obtained thin films possessed high dielectric constant, eps ilon(r) = 1346 and tan delta = 0.071 at 10 kHz, and large charge stora ge density, Q(c) = 5.4 muC/cm2 at 50 kV/cm.