Compositional variation of metallorganic chemically vapor deposited SrTiO3 thin films along the capacitor hole having a diameter of μm

Variations in the cation concentration ratio of metallorganic chemically vapor deposited SrTiO3 (STO) thin films along a capacitor hole having a diam of 0.15 mum, were investigated. Even under the deposition conditions that produce stoichiometric STO films on a nonpatterned wafer, the Sr/Ti ratio is greatly decreased along the depth direction of the hole. The degree of variation depended on the flow rate of the precursors. In some cases, a film having a Ti concentration of more than 90% was deposited at the bottom of the hole with a Ti concentration of less than 30% at the top of the hole. A plausible reason for the compositional variation was suggested on the basis of the decreased diffusion speed of the precursor molecules in the small sized holes. (C) 2001 The Electrochemical Society.