Effects of Postannealing in Oxygen Ambient on Leakage Properties of (Ba, Sr)TiO₃ Thin-Film Capacitors

Abstract

Effects of postannealing in oxygen ambient on the leakage properties of sputter-deposited (Ba, Sr)TiO 3 (BST) thin-film capacitors with Pt electrodes are investigated as a function of oxygen gas pressure, postannealing temperature and postannealing time. It is shown that the leakage properties can be improved by increasing these conditions. By comparing the leakage behavior with a Schottky emission model, it is concluded that the main effect of postannealing is an increase in the Pt/BST Schottky barrier height. It is also shown that the Fermi level of the BST film may be pinned at the Pt/BST interface because of oxygen vacancies in the film.