Improved dielectric and insulating properties of Ba0.5Sr0.5TiO3 films fabricated by laser molecular-beam epitaxy with active oxygen

Ba0.5Sr0.5TiO3 (BST) thin films were deposited epitaxially on Nb-doped SrTiO3 (STN) substrate by laser molecular-beam epitaxy with active oxygen. Via Pt/BST/STN capacitor structure, influences of active oxygen on electric properties were investigated within the temperature range from 80 to 340 K. It was found that temperature stability of BST film permittivity was improved dramatically with using of active oxygen. Moreover, the BST thin film deposited with active oxygen exhibited better electric properties: high dielectric constant, low loss tangent, large tunability of permittivity, and low leakage current. The results demonstrate that the using of active oxygen in deposition process is an effective method to improve dielectric and insulating properties of BST film.