Low temperature chemical vapor deposition of (Ba, Sr) TiO3 thin films with Ti(mpd)(tmhd)(2) as a Ti source

Abstract

The deposition characteristics of (Ba, Sr)TiO3 (BST) thin films with direct liquid injection metallorganic chemical vapor deposition on a Pt/SiO2/Si wafer were investigated. A single cocktail solution of Ba(methd)(2) (methd = methoxyethoxytetramethylheptanedionate), Sr(methd)(2), and Ti(mpd)(tmhd)(2) (mpd = methylpentanediol, tmhd = tetramethylheptanedionate) with methanol solvent was used as a precursor. Ti(mpd)(tmhd)(2) as a Ti precursor showed better thermal stability than did Ti(i-OPr)(2)(tmhd)(2), and alleviated Ti-rich hump regions due to the weak Ti-(i-OPr) bond strength of Ti(i-OPr)(2)(tmhd)(2). Some haziness in the film was observed when the reactor pressure was increased. Conformal step coverage (>90%) and good electric properties (leakage less than 2 x 10(-7) A/cm(2) at 1 V) were obtained. (C) 2001 The Electrochemical Society.