Kinetics and Breakdown Voltage Studies of Tantalum - Tantalum Oxide - Electrolyte Systems

Authors: Parveen Katyal

Country: India

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Abstract: Steady state kinetic data and breakdown voltage studies of anodic oxide thin films on tantalum in various aqueous electrolytes have been obtained. The above data has been obtained at different current densities, field strength, temperature, composition, concentration and resistivity of the Electrolytes. These studies have been made by eliminating the difference of film growth caused by different surface conditions. The rate of increase of field strength with logarithm of ionic current density is independent of temperature. The data show same relation between electronic current and field holds irrespective of film thickness. A direct relation between electronic current and breakdown voltage has been observed. The maximum thickness reached during the growth of Anodic oxide film on tantalum and other metals is limited by electrical breakdown. The effect of electrolyte concentration on breakdown voltage can be explained in terms of Ikonopisov electron injecting avalanche model. The major factor contributing to the decrease in breakdown voltage with increase in electrolyte concentration is its increasing primary electronic current. The values of the parameters for impact ionization coefficient and primary electronic current have been evaluated. Appearance of sparking is found to be superior method for identifying breakdown voltage during formation of Tantalum oxide films. It has been found field strength is independent of film thickness up to certain formation voltage and at higher formation voltages, the dependence of field strength on film thickness was observed.

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Paper Id: 1642

Published On: 2013-10-15

Published In: Volume 1, Issue 1, September-October 2013

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