Low dielectric dissipation and enhanced tunability of Ba0.6Sr0.4TiO3 thin films by the modified composition and multilayer structure

Ba0.6Sr0.4Ti1+yO3 (BST, y = 0.1, 0.15, 0.2, 0.25, 0.3) thin films were fabricated on Pt-coated silicon substrates by modified sol-gel techniques. It was found that the tunability of BST thin films and dissipation factor decreased with the increase of Ti content. The multilayer structure of Ba0.6Sr0.4Ti1+yO3(200 nm)/Ba0.6Sr0.4TiO3(100 nm)/Ba0.6Sr0.4Ti1+yO3 (200 nm; y = 0.1, 0.2, 0.25) was designed to enhance the tunability. Our results indicated that the modified composition and multilayer structure were beneficial to lowering the dielectric dissipation and enhancing the tunability simultaneously. The tunability of 26.7% and dielectric dissipation of 0.013 were achieved for modified BST thin films.