Net spontaneous polarisation in As-grown SET films

SrBi2Ta2O9 ferroelectric thin films have been deposited by metalorganic decomposition (MOD) on Pt/TiO2/SiO2/(100)Si substrates. Crystallisation of the spun-on films was carried out under O-2 flow, at temperatures of 750 degreesC for times that ranged from 10 to 60 minutes. The resulting 300 nm thick films were orthorhombic single phase and random or slightly < 100 >/< 010 > oriented, as determined by XRD. A relative strong net polarisation, in comparison with the available switched value, has been measured by a novel method used to trace the first hysteresis loop. Remnant polarisation values, Pr congruent to 5 9 muC/cm(2), and leakage current densities below 10(-7) A/cm(2) at 3 V have been obtained. No significant fatigue was observed after 10(10) write/read cycles and P-r was retained for up to 10(5) s. Results are discussed on the basis of the films texture and microstructure. Net polarisation results indicate that only switching of 180 degrees domains occurs, taking into account that the polar direction lies along the a-axis.