A thin TiO2 buffer layer was used to control the microstructure and electrical properties of the polycrystalline (Pb,Sr)TiO3 (PST) films produced by a Sol-Gel method on Pt(111)/Ti/SiO2/Si(100) substrates. The PST films included (Pb0.6ST0.4)TiO3 (PST40) and (Pb0.4Sr0.6)TiO3 (PST60). It was found that a crystallized TiO2 buffer layer with a thickness of nearly 5 nm was critical for improving the crystallinity and surface morphology of both the thinner (about 40 nm) and thicker (about 330 nm) PST films, which exhibited a (100) preferred orientation and much smoother surface comparing with those without the buffer layer. The electrical properties of the PST films having TiO2 buffer layer were also improved. For 330-nm-thick PST40 films, the dielectric constant and its tunability by dc voltage were increased from 482 and 26.8% at 10 kHz to 590 and 51.2%, while the loss and leakage current density were reduced from 0.04 and 4.26 x 10(-4) A/cm(2) at 100 kV/cm to 0.034 and 7.63 x 10(-6) A/cm(2), respectively. Similar results were also found in the PST60 films. (C) 2007 Elsevier B.V. All rights reserved.