BaxSr1-xTiO3 (BST) films are fabricated by sol-gel and RF (radio frequency) magnetron sputtering method. A buffer layer with columnar grains by sol-gel method is introduced to improve the dielectric anomaly in BST films. We find that the presence of buffer layer can increase the differential dielectric constant against temperature in sol-gel derived BST films while not so with sputtered films. We explain this by an 'expanded layer thickness model' and an unstable crystallized surface, respectively. The obtained (depsilon/epsilon) dT is up to 6% around 11 degreesC by the sol-gel method. (C) 2002 Elsevier Science Ltd. All rights reserved.