Formation of Al2O3-Ta2O5 Double-Oxide Thin Films by Low-Pressure MOCVD and Evaluation of Their Corrosion Resistances in Acid and Alkali Solutions

Nobuyoshi Hara, Shintaro Nagata, Noboru Akao, Katsuhisa Sugimoto

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Electrochemical Society Active Member Al2O3-Ta2O5 double-oxide thin films with different cationic mole fractions of Ta, XTa, were formed by metallorganic chemical vapor deposition using aluminum tetraisopropoxide [Al(O-i-C3H7)3] and tantalum pentametoxide [Ta(OCH3)5] as source gases and oxygen as a reaction gas. The corrosion resistances of the films were examined in 6 and 12 M HCl and l M NaOH at 298 K by the ellipsometric measurement of thinning rates of the films. The Al2O3-Ta2O5 films having XTa values between 0.0 and 1.0 showed homogeneous amorphous structures. The thinning rate of the films in HCl solutions decreased with increasing XTa value and reached the analytical limit of ellipsometry. The films with XTa values larger than 0.35 hardly dissolved in 6 M HCl and those with XTa values larger than 0.45 in 12 M HCl. The corrosion resistance of the Al2O3-Ta2O5 films in l M NaOH increased significantly with an increase in XTa: the dissolution rate of the Al2O3-Ta2O5 film with XTa value of about 0.5 is lower than that of pure Al2O3 film by six orders of magnitude.

Original languageEnglish
Pages (from-to)510-516
Number of pages7
JournalJournal of the Electrochemical Society
Volume146
Issue number2
DOIs
Publication statusPublished - 1999

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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