title: Corrosion Resistance of Atomic Layer Deposition-Generated Amorphous Thin Films.
abstract: Atomic layer deposition (ALD) was used to prepare amorphous thin films of Al2O3, Nb2O5, and Ta2O5on both silicon substrates and aluminum blocks. Etch rates in 10 M NH4OH were determined from X-ray reflectometry data collected as a function of time. Amorphous Al2O3thin films were found to have an etch rate of 0.5 nm min-1and an increase in roughness of ∼0.01 nm min-1. Electron microscopy data showed etch pits, consistent with the increase in roughness. Amorphous Nb2O5and Ta2O5films showed no appreciable etching or roughening over the course of a ∼500 h continuous immersion. An Nb2O5-coated aluminum block showed no corrosion after immersion in 10 M NH4OH for over 200 h, suggesting that the coatings were pinhole-free. These results suggest that amorphous ALD thin films of Nb2O5and Ta2O5are candidates as barrier layers for aluminum in caustic environments.
authors.affiliation: Department of Chemistry, 1253 University of Oregon , Eugene, Oregon 97403, United States.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Anderson
authors.affiliation: MLD Technologies LLC, 1000 South Bertelsen Road #14, Eugene, Oregon 97402, United States.
authors.forename: Brad
authors.initials: B
authors.lastname: Aitchison
authors.affiliation: Department of Chemistry, 1253 University of Oregon , Eugene, Oregon 97403, United States.
authors.forename: David C
authors.initials: DC
authors.lastname: Johnson
keywords: X-ray reflectivity; aluminum corrosion; atomic layer deposition; corrosion protection; protective coatings