An investigation of structures of thermal and anodic tantalum oxide films

Document Type

Article

Publication Date

3-17-2005

Abstract

Tantalum oxide films produced from anodic oxidation and thermal oxidation at 400 and 800°C have been investigated with respect to long- and short-range structure by X-ray diffraction and X-ray absorption spectroscopy, respectively. Films formed at 800°C show orthorhombic structure (β-Ta2O5) with greater disorder compared to the β-Ta2O5 powder reference, where six O atoms were observed at an avenge radial distances of 1.957 ± 0.014 (Ta2O, powder) and 1.971 ± 0.007 Å (800°C Ta oxide film). Lower temperature films consist primarily of metastable TaOx (Ta 2O) and appear to be relatively stable for extended times of treatment with a first shell not unlike that of β-Ta2O 5, based on a linear combination analysis. Furthermore, using a linear combination of β-Ta2O5 and α-Ta metal, the amorphous anodic oxide films studied as a function of thickness were observed to exhibit a relatively ordered local structure consistent with the high-temperature (i.e., 800°C) phase. This work demonstrates that the nanoscale oxide films formed on tantalum exhibit an ordered local structure, reflecting the very compact nature that enhances its corrosion resistance. © 2005 The Electrochemical Society. All rights reserved.

Identifier

14744269610 (Scopus)

Publication Title

Journal of the Electrochemical Society

External Full Text Location

https://doi.org/10.1149/1.1850362

ISSN

00134651

First Page

B60

Last Page

B64

Issue

2

Volume

152

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