Low temperature deposition of Ba1-xSrxTiO3 thin films by ECR plasma-enhanced metalorganic chemical vapor deposition

Abstract The deposition temperature dependence of Ba0.7Sr0.3TiO3 (BST) thin film physical and electrical properties was investigated. Films were deposited between 250 and 500°C by electron cyclotron resonance (ECR) plasmaenhanced liquid source metalorganic chemical vapor deposition (MOCVD). Depositions were carried out in an oxygen plasma using the precursors Ba(thd)2•(polyamine), Sr(thd)2•(polyamine), and Ti(O-i-Pr)2(thd)2. With a constant ECR plasma power, composition and growth rate were independent of temperature within the full range investigated, in contrast to most thermally-driven CVD BST processes. Films grown above 350°C were crystalline as-deposited on Pt, and were (100)-textured. The dielectric properties depended strongly upon BST crystallinity, with a sharp increase in dielectric constant and its field dependence observed above 350°C. For slightly Ti-rich, 800A thick films, dielectric constants of 281 were obtained at 500°C, following a 550°C top electrode anneal in O2. Over the full deposit...