Growth and structural evolution of La0.5Sr0.5CoO3 thin films fabricated directly on SiO2/Si substrate by pulsed laser deposition were investigated. Films deposited at 780 degrees C and oxygen partial pressure of 2 Pa showed highly c-axis orientation. Films with low electrical resistivity of 2 X 10(-3) Omega cm were obtained by annealing at 650 degrees C for 40 min. C-axis oriented Ba0.5Sr0.5TiO3 thin film was then grown on the La0.5Sr0.5CoO3 film, and large dielectric tuning (> 50%) was achieved. This method may have good prospect for the integration of ferroelectric, materials with conventional Si process technology. (c) 2005 Published by Elsevier B.V.