(TiO2)(x)-(Ta2O5)(1-x) thin films were prepared with radio-frequency magnetron sputtering deposition in this study. The dielectric constant measured from these films appears to critically depend on the amount of TiO2 incorporated into the film and post-anneal condition. The composition dependence was found similar to that reported on (TiO2)(x)-(Ta2O5)(1-x) bulk. The highest value of dielectric constant is about 55 for a TiO2 content of 8% and annealing at 800 degrees C. Compared to pure Ta2O5 thin films, significant enhancement in dielectric constant is obtained by adding small quantity of TiO2. (C) 1998 American Institute of Physics.