Abstract: Barium strontium titanate，Ba_0.7Sr_0.3TiO₃ thin films with good electrical properties were prepared on Pt/Ti/SiO_2/Si (100) substrates by a
modified sol-gel processing with a new precursor solution，ethylene glycol was introduced as a necessary component of the solution to increase the stability of
precipitation and to decrease the crystallization temperature of films. The thermolysis process of the BST-gel was analyzed by DTA and XRD, and the effects
of thickness on phase formation were investigated. A dielectric constant >400 and a dissipation factor <0.02 were measured at 100kHz for BST films heated to 700℃ for 15min in O₂ with a thickness of 200nm. P-E hysteresis loop
studies indicated a remanent polarization (P_r) of 1.4μC/cm² and a coercive field (E_c)of 48kV/cm .

Key words: BST thin films, sol-gel method, ethylene glycol, P-E hysteresis loop