摘要 |
A device comprising a dielectric oxide film formed by anodization of a surface region of a valve metal body, a semiconductive metal oxide layer porously formed on the dielectric oxide film, and a gas permeable electrode layer formed on the semiconductive metal oxide layer with the interposal of a gas permeable carbon layer therebetween. The semiconductive metal oxide layer is formed by pyrolysis of a metal salt solution so as to be, microscopically, only partially in contact with the dielectric oxide film. After forming of the electrode layer, the device is immersed in boiling water and/or kept in a high temperature high humidity atmosphere for an adequate amount of time to stabilize the semiconductive metal oxide layer, resulting in that the semiconductive metal oxide layer has a multiplicity of microscopic crevices and that the device becomes quite stable in the relation between humidity and electrostatic capacitance of the device. |