Postdeposition reactivity of sputter-deposited high-dielectric-constant films with ambient H2O and carbon-containing species

The room temperature reactivity of group III and IV based high-dielectric-constant films during long-term (>1 year) exposure to ambient atmosphere (H2O- and C-containing species such as CO2) has been studied in order to assess the stability of the materials. We prepare the films by physical vapor deposition of metal on Si (100) surfaces which is followed by oxidation in N2O (1 atm), and monitor the formation of carbonate/alkoxylate and hydroxide species using Fourier transform infrared spectroscopy. For La-based films we find that the oxidation temperature has a strong effect on the reactivity with the ambient. For Hf- and Zr-based films, formation of various carbonate or alkoxylate species is confirmed within minutes of exposure, while substantial reaction with H2O is not detected. Hf-based films, in general exhibit superior stability upon long-term exposure. (C) 2004 American Institute of Physics.