THE GROWTH AND PROPERTIES OF THIN OXIDE LAYERS ON TANTALUM ELECTRODES

被引:114
作者
MACAGNO, V
SCHULTZE, JW
机构
[1] Univ Duesseldorf, Inst fuer, Physikalische Chemie, Duesseldorf,, West Ger, Univ Duesseldorf, Inst fuer Physikalische Chemie, Duesseldorf, West Ger
来源
JOURNAL OF ELECTROANALYTICAL CHEMISTRY | 1984年 / 180卷 / 1-2期
关键词
ELECTRODES; ELECTROCHEMICAL - Tantalum - HYDROGEN ION CONCENTRATION - SEMICONDUCTOR MATERIALS - TANTALUM COMPOUNDS;
D O I
10.1016/0368-1874(84)83577-7
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
The dependence of the growth of thin oxide films on tantalum electrodes on the electrode potential (0 v less than E less than 10 v) and pH (0 less than pH less than 14) was investigated by coulometric and simultaneous impedance measurements. After chemical polishing, there is a thin film of about 2 nm thickness. At anodic polarization, the film grows by 1. 76 nm/v. The dielectric constant D is about 25. Various anions have no influence, but the pH shifts the oxide growth by minus 60 mv per pH unit. Thin films behave as n-type semiconductors, and show a Schottky-Mott behavior at negative potentials E less than 0 v. The donor density decreases with increasing thickness so that films thicker than 10 nm behave as pure insulators. Cathodic hydrogen evolution takes place at large overvoltages of about less than 1 v. The characteristic potentials of passive tantalum are compared and discussed.
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页码:157 / 170
页数:14
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