Experimental and Simulation Study of BaTiO ₃ -Based Thin Films Deposited by Pulsed Laser Deposition for Piezoelectric Applications

Lead (Pb)-free piezoelectric thin films are gaining attention due to their versatility in microelectromechanical systems (MEMS), including actuator, sensor, and memory applications. In the present work, pristine and doped BaTiO3 (BTO) ferroelectric polycrystalline thin films with chemical configuration Ba0.95Ca0.05Sn0.09Ti0.91O3 (BCST) were deposited on the SrTiO3 substrate by the pulsed laser deposition (PLD) technique. X-ray diffraction and Raman patterns ensure the formation of a pure phase tetragonal structure in both films. Cross-sectional focus ion beam scanning electron microscopy (FIB-SEM) analysis of the films revealed densely packed columnar structures in each layer, showing strong interlayer bonding. The BCST film shows a high value of saturation polarization of 37.53 μC/cm2 as well as dielectric constant of 175 as compared to the BTO film at room temperature. This linear enhancement is due to Ca2+ substitution at the Ba2+ site and Sn4+ substitution at the Ti4+ site. These substitutions introduce lattice distortion and displacement of Ti ions in the TiO6 octahedral geometry, which enhances the polarization as well as the dielectric constant. Furthermore, the films have a very high effective piezodisplacement of about 992 pm and converse piezoelectric coefficient (d33*) of about 49.6 pm/V. The COMSOL simulation results show good qualitative agreement and similar trends with the experimental data, confirming the validity of the modeling approach. This study demonstrates the potential of Pb-free BaTiO3-based films and their applications in piezoelectric sensors/actuators and pulsed power devices.