Properties of Oxide Film Atomic Layer Deposited from Tetraethoxy Silane, Hafnium Halides, and Water

Abstract

Hafnium silicate thin films were grown by atomic layer deposition at 300 and 500°C on HF-etched silicon and borosilicate glass substrates. The films were grown by alternating exposure of the substrate surface to gaseous Si(OC2H4)4 and HfI4 or HfCl 4 flows. H2O was used as an additional oxygen precursor in hydrolysis reactions. Silicate films were also grown without H2O. The application of H2O resulted in increased growth rate and improved density and dielectric performance of the films. The silicate films were amorphous. Their effective permittivity typically varied between 6 and 10. The composition of the films, determined by ion beam analysis, was uniform throughout the film thickness, approaching the stoichiometry of HfSiO 4. X-ray photoelectron spectroscopy revealed that the thinnest films grown were somewhat silicon-rich. The silicon content was twice the hafnium content. Low amounts of residual chlorine, iodine, and carbon (<0.1-2 atom %) were detected in the as-deposited films. © 2004 The Electrochemical Society. All rights reserved.