Ferroelectric Ba(Sn0.15Ti0.85)O-3 (BTS) thin films were deposited on LaNiO3-coated silicon substrates via a sol-gel process. Films showed a strong (100) preferred orientation depending upon annealing temperature and concentration of the precursor solution. The dependence of dielectric and ferroelectric properties on film orientation has been studied. The leakage current density of thin films at 100 kV/cm was 7 x 10(-7) A/cm(2) and 5 x 10(-5) A/cm(2) and their capacitor tunability was 54 and 25% at an applied field of 200 kV/cm (measurement frequency of 1 MHz) for the thin films deposited with 0.1 and 0.4 M spin-on solution, respectively. This work clearly reveals the highly promising potential of BTS compared with BST films for application in tunable microwave devices. (C) 2004 Elsevier Ltd. All rights reserved.