Ferroelectric properties of sol-gel-derived PbTiO3 type thin films

The degradation of ferroelectric properties with decreasing film thickness is a common problem of PbTiO3 type ferroelectric thin films. We suspected that this degradation was caused mainly by oxygen vacancies that diffused from the film surface through the grain boundaries during firing. Thus we have been attempting Al3+ substitution for Ti4+ in PbTiO3 using a sol-gel method. In this study, the relationship between the ferroelectric properties of Pb(Ti0.85Al0.15)O-3-x, thin films and the firing conditions in the thin film preparation process was investigated. The 0.14-mu m-thick Pb(Ti0.85Al0.15)O-3-x, films fired at 700 degrees C for 15min in air exhibited good ferroelectric properties. For these firing conditions; the dielectric constant, remanent polarization and coercive field were epsilon = 3561 Pr = 9 mu C/cm(2) and Ec = 84kV/cm, respectively.