Barium strontium titanate ((Ba, Sr)TiO3) thin films were prepared on Pt/Ti/
Si substrates by the sol-gel method using metal alkoxides. The dependence o
f the dielectric constant for the films on the film compositions and on the
film thickness were investigated. The dielectric constant of the fi Im of
thickness 180 nm had the highest value of 230 at composition ratios of [Ba
+ Sr]/[Ti] = 1.04 and [Sr]/[Ba + Sr] = 0.6. The dielectric constant of the
films with this composition decreased from 390 to 160 with a decrease in th
e film thickness from 440 to 100 nm. The decrease in the dielectric constan
t with increasing film thickness is attributed to the existence of a low-di
electric-constant interface layer adjacent to the electrodes. (C) 1998 Kluw
er Academic Publishers.