FERROELECTRIC PROPERTIES OF SOL-GEL-DERIVED PBTIO3 TYPE THIN-FILMS

The degradation of ferroelectric properties with decreasing film thick ness is a common problem of PbTiO3 type ferroelectric thin films. We s uspected that this degradation was caused mainly by oxygen vacancies t hat diffused from the film surface through the grain boundaries during firing. Thus we have been attempting Al3+ substitution for Ti4+ in Pb TiO3 using a sol-gel method. In this study, the relationship between t he ferroelectric properties of Pb(Ti0.85Al0.15)O-3-x, thin films and t he firing conditions in the thin film preparation process was investig ated. The 0.14-mu m-thick Pb(Ti0.85Al0.15)O-3-x, films fired at 700 de grees C for 15min in air exhibited good ferroelectric properties. For these firing conditions; the dielectric constant, remanent polarizatio n and coercive field were epsilon = 3561 Pr = 9 mu C/cm(2) and Ec = 84 kV/cm, respectively.