Dielectric properties and high tunability of (100)- and (110)-oriented (Ba0.5Sr0.5)TiO3 thin films prepared by pulsed laser deposition

Abstract (Ba 0.50 Sr 0.50 )TiO 3 (BST) thin films were deposited on Pt(1 1 1)/Ti/SiO 2 /Si(1 0 0) substrates without and with LaNiO 3 (LNO) bufferlayer prepared by pulsed laser deposition (PLD). The BST thin films directly grown on Pt/Ti/SiO 2 /Si substrates without and with LNO bufferlayer exhibited highly (1 0 0) and (1 1 0) orientation, respectively. The dielectric constant of the 800-nm-thick BST films with LNO bufferlayer was 1010 at 1 MHz, which was higher than that of BST film with non-bufferlayer (∼851). Also, the tunabilities of BST thin films with (1 0 0)- and (1 1 0)-orientation were ∼63% and ∼62%, respectively, at the applied field of 262.5 kV/cm. Improved dielectric constant has been attributed to LNO bufferlayer.