Dielectric properties of epitaxial Ba_(0.6)Sr_(0.4)TiO_(3) films on SiO_(2)/Si using biaxially oriented ion-beam-assisted-deposited MgO as templates

摘要

We have epitaxially deposited Ba_(0.6)Sr_(0.4)TiO_(3) (BST) thin films on SiO_(2)/Si substrates using pulsed laser deposition by introducing biaxially oriented ion-beam-assisted-deposited MgO as templates. The structural properties of the BST films were strongly affected by the crystallinity of the templates. The dielectric loss of the BST film was found to decrease as its in-plane texture alignment was improved. As a result, a relatively larger figure of merit K value, defined as tunability/loss, was obtained for the films with better in-plane crystallinity. The K factor ranged between 7.5 and 3.5 when the in-plane alignment of the MgO templates was varied from 5.0° to 10.5°. This work demonstrates that the crystalline quality of the template layers plays a critical role in monolithic integration of BST with SiO_(2)/Si for frequency agile devices.