Characterization of a tantalum capacitor fabricated with a conducting polypyrrole as a counter electrode

Summary form only given. A tantalum solid electrolytic capacitor using a conducting polypyrrole com posite as a counter electrode has been investigated on the current-voltage characteristics at various temperatures. The capacitor demonstrates the features of an ideal capacitor, meaning a constant capacitance and proportion al decrease of impedance with frequency up to the resonance point. The leak age current at the working voltage is nearly two orders of magnitude smaller than of a conventional tantalum capacitor using a MnO/sub 2/ electrode. The resistance changes along the curve expected from the variable range hopping model similarly to the case of polypyrrole alone. The current-voltage curve follows the Schottky or Pool-Frenkel emission process and shows that the area and depth of the defects on dielectric (Ta/sub 2/O/sub 5/) layers are smaller than those of the conventional tantalum capacitor. Furthermore, the healing effect is observed for broken samples. In this case, the current decreases dramatically by applying the working voltage.