Structural characterization of ZrO2 thin films produced via self-assembled monolayer-mediated deposition from aqueous dispersions

Thin ZrO2 films were produced at 323 K by the deposition of colloids from stable, aqueous dispersions (formed from 4 mM Zr(SO4)(2) in 0.4 N HCl) onto silicon wafer-supported, functionalized self-assembled monolayers (SAMs). The deposition took place without visible bulk precipitation. As-deposited and heat-treated films were characterized by high-resolution transmission electron, analytical electron and scanning electron microscopy. In each case, an amorphous layer was found between the Si single crystal and the nanocrystalline ZrO2 film. The amorphous layer of the as-deposited films was found to be composed of two distinct layers: SAM and SiO2. Upon heat treatment at 773 K for 2 h in air or Ar, the SAM layer was no longer observed, suggesting that it decomposes and is removed completely in either atmosphere. The as-deposited films had a grain size of similar to 5 nm throughout the film thickness. Following heat treatment, a slight increase in grain size was observed. Deposition without the SAM was also attempted, but failed to produce a strongly adherent, uniform film. (C) 2000 Elsevier Science B.V. All rights reserved.