Heat‐Treatment of Anodic Oxide Films on Tantalum: I . The Effects on Dielectric Properties

Abstract

When anodized tantalum is subjected to temperatures in excess of 200°C, the equivalent series capacitance, equivalent series resistance, and temperature, frequency, and bias dependences of these properties increase. These phenomena are interpreted as resulting from the extraction of oxygen from the dielectric oxide by the tantalum substrate. This process creates an oxygen‐deficient region in the oxide whose semiconductivity causes the above‐mentioned changes in dielectric properties. Reanodization of the sample removes the effects associated with the conductivity. A small increase in apparent dielectric constant, which also results from heat‐treatment, is a permanent effect.