Metalorganic chemical vapor deposition of c-axis oriented PZT thin films

Ferroelectric PZT thin films were prepared by the simultaneous deposition of PbO, ZrO2 and TiO2 on heated substrates under a reduced pressure of 6 Torr. Both tetrethyl lead-zirconium tetraisopropoxide and tetradipivaloylmethane-titanium tetraisopropoxide systems were examined as source materials. The films obtained at 500° to 650°C with those systems were constituted of PZT of the single perovskite phase, and highly c-axis-oriented films were grown on MgO(100) with the latter system. The c-axis orientation suggests an epitaxial growth of PZT on the substrates. With increasing molar fraction of ZrO2 in the PZT, the crystals were transformed from a tetragonal to rhombohedral structure. The film deposition rates were 100 to 1000 angstrom/min, i.e., more than ten times those obtained by the conventional sputtering method.