Barium strontium titanate (BSTO) films were synthesized by the pulsed laser deposition technique (PLD) on silicon substrates at room temperature. The BSTO film synthesis took place at constant laser energy, 500 mJ, and partial oxygen pressure of 3, 15, 30, 45, 100 mTorr. All films were post annealed at 750 °C in a tube furnace in an oxygen atmosphere. The microstructure, crystallinity and lattice constant of the BSTO films were studied with the aid of scanning electron microscopy (SEM), photon tunneling microscopy (PTM) and Glancing Angle X-ray Diffraction analysis (GAXRD). The hardness and modulus of elasticity of the films were studied with the aid of a nanohardness indenter. The film stoichiometry was determined with the aid of Rutherford Back Scattering (RBS). The results of this research will be combined with the results of our previous work  on the effect of substrate temperature on the microstructure and mechanical properties of the BSTO films in order to construct a structural zone model (SZM) of the BSTO films synthesized by PLD.