Investigation of interface and oxygen vacancy of Pt/Ba0.6Sr0.4TiO3/MgO interdigital capacitor through sequent low and high temperature annealings

Abstract

Pt/Ba[Formula: see text]Sr[Formula: see text]TiO[Formula: see text] (BST)/MgO interdigital capacitor (IDC) was patterned from a Pt/BST/MgO heterostructure, in which Pt film was prepared by sputtering and epitaxial BST film by pulsed laser deposition (PLD). Post-annealings at 200[Formula: see text]C and 750[Formula: see text]C were successively applied to the sample in order to investigate the impacts of post-annealing on the structural and dielectric properties of the IDC. The dielectric constants of the sample for as-grown and annealed at 200[Formula: see text]C and 750[Formula: see text]C were 1529, 1717 and 1800 and the corresponding dielectric losses were 0.073, 0.062 and 0.059, respectively. This is attributed to the fact that 200[Formula: see text]C annealing can improve the quality of Pt/BST interface and 750[Formula: see text]C annealing can reduce the oxygen vacancies in BST film. Our results provide the evidences that both the interface and oxygen vacancy play very important roles in dielectric properties of BST-based IDCs.