Surface chemical bonding states and ferroelectricity of Pb(Zr0.52Ti0.48)O3 thin films

The surface chemical bonding states and the ferroelectric properties of sol-gel deposited lead zirconate titanatt [Pb(Zr0.52Ti0.48)O-3, PZT] thin films coated on (111)Pt/Ti/SiO2/Si substrates were investigated. Xray photoelectron spectroscopy (XPS) was used to determine the oxidation state of the surface and the chemical composition as a function of depth in ferroelectric PZT thin layers. Values for the dielectric constant and dissipation factor at 1 kHz for the 300 nm-thick film were 1214 and 0.014 for the film annealed at 520 degrees C, and 881 and 0.015 for a film annealed at 670 degrees C. Measured values for the remanent polarization (P-r) and coercive field (E-c), from polarization-electric field (P-E) hysteresis loops biased at 10 V at a frequency of 100 Hz, were 16.7, 14.3 mu C/cm(2) and 60, 41.7 KV/cm for 520 degrees C and 670 degrees C. The leakage current density (J) was 72 and 96 nA/cm(2) at an applied field of 100 kV/cm. It was found that the bonding states of lead and oxygen in the surface regions could be correlated with the ferroelectric properties of the integrated thin layers.