Radio‐frequency sputtered barium titanium silicate (BST), Ba2Si2TiO8, thin films were grown on crystalline Si(100) substrates at substrate temperatures ranging from 750 to 955 °C and were characterized using x‐ray diffraction, optical microscopy, and scanning electron microscopy. The result of x‐ray diffraction analysis indicates that the BST films deposited at an optimum substrate temperature of 845 °C were stronglyc‐axis oriented. The corresponding film growth rate in the direction normal to the film surface and lateral grain growth rate were 1.95 nm/min and 0.77 &mgr;m/min, respectively, at the initial stage of deposition. The former decreased with sputtering time and the latter increased with grain size. The fast lateral grain growth rate indicates a strong interaction between the overgrown BST film and the Si substrate. The increase in lateral grain growth rate suggests a surface diffusion controlled nucleation and growth mechanism in the initial stage of the deposition, and a coalescence mechanism dominating in the later stage. The activation energy for lateral grain growth was 359±30 kJ/mol for 0.01 &mgr;m size grains, and decreased to 148±20 kJ/mol for 1 &mgr;m size grains, which is in good agreement with the proposed growth model.