PbxSr1-xTiO3 (PST) thin films with the ratio Pb/Sr similar to=similar to 40/60 were deposited on silicon substrate with Pt or LaNiO3 (LNO) bottom electrodes by radio frequency magnetron sputtering followed by a postannealing treatment. The structural and microstructural analyses were performed and a perovskite phase was obtained whatever the nature of the bottom electrodes and even at a low temperature (450 degrees C). The optimal annealing temperature is 650 degrees C at which the films have a dense and fine microstructure. For electrical characterization the different top electrodes (Pt and LNO) were used. In both cases, we demonstrate that PST films present excellent performances in terms of dielectric properties and in particular, the tunability and Figure of Merit. A large tunability (57% at 400 similar to kV/cm) and low dielectric losses (1.4%) were measured at 10 similar to kHz for Pt/PST/Pt structures postannealed at 500 degrees C. For LNO/PST/LNO structures, postannealed at 650 degrees C, the improved tunability (similar to 80%) and low loss factor (similar to 2%) were obtained. Prospects of PST as an alternative to BST for tunable applications with a real potentiality of monolithic integration with silicon, in terms of thermal budget, are considered.