Characterization of single layer PZT (53/47) films prepared from an air-stable sol-gel route

Single layer Pb(Zr_0.53Ti_0.47)O₃films up to 0.7 μm thick have been prepared from air-stable titanium and zirconium precursors using a diol-based sol-gel route. Information on film crystallization, surface microstructure, and electrical properties under different firing temperatures and three different heating rates including rapid thermal annealing are presented. Films exhibited (111) preferred orientation, the extent of which reduced with increasing firing temperature or heating rate. It is possible that a PbPt_xinterfacial reaction product was formed during the prefiring step at 350 °C and this, together with the influence of the 111 bottom platinum electrode, contributed to (111) orientation in the PZT films. Surface microstructure was also influenced by firing temperature and heating rate as well as by film thickness. The 0.4 μm thick films used for electrical measurement had a grain size of ⋚0.1 μm, whereas 0.7 μm thick films made from concentrated sols exhibited “rosette” microstructures with grain sizes up to 0.5 μm. Among the three firing schedules studied, directly inserting the gel coatings in a furnace preset at 700 °C produced films with the most favorable electrical properties. A 0.4 μm thick film gave rise to a remanent polarization,P_r, of 33 μC cm⁻²coercive field,E_c, of 46 kV cm⁻¹; relative permittivity, ∊_r, of 1100; and dissipation factor,D, of 0.05. For a 0.7 μm single layer film, the respective values were 21 μC cm⁻², 36 kV cm⁻¹, 1300, and 0.05.