In this work, Ba0.6Sr0.4TiO3 (BST) films were deposited on Si(100) and Pt(111)/Ti/SiO2/Si(100) substrates using the pulsed laser deposition (PLD) technique. The effects of TiO2 buffer layer thickness and preparation temperature on the microstructure and electrical properties of BST films were studied in detail. We intensively investigated the influence of the TiO2 buffer layer on the microstructure of BST films by using X-ray diffraction and scanning electron microscopy. We found that anatase crystalline TiO2 buffer layers within 15 nm thicknesses could significantly change the BST films from an irregular orientation to the (111) preferential orientation. The TiO2 anatase layers could promote the growth of BST film grains for obtaining minimal stress and low lattice distortion, increase the nucleation density, and improve its surface morphology, resulting in higher dielectric constant and resistance voltage, and lower dielectric loss and leakage current density. The dielectric constant, dielectric loss, and dielectric tunability of the BST devices with 8 nm thick TiO2 anatase buffer layers at 1 MHz were 856.5, 0.017, and 64.3%, respectively. The achieved high dielectric tunability indicates BST with TiO2 anatase buffer layers as one of the encouraging candidates for RF and microwave tunable applications at room temperature.
Wang et al. (Fri,) studied this question.