Dielectric properties and high tunability of (100)- and (110)-oriented (Ba_(0.5)Sr_(0.5))TiO_3 thin films prepared by pulsed laser deposition

摘要

(Ba_(0.50)Sr_(0.50))TiO_3 (BST) thin films were deposited on Pt(111)/Ti/SiO_2/Si(100) 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 (100) and (110) 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 (100)- and (110)-orientation were ～63% and ～62%, respectively, at the applied field of 262.5 kV/cm. Improved dielectric constant has been attributed to LNO bufferlayer.