Theory and analyses of the ac characteristics of defect thin-film insulators

Abstract

In the past, ac properties obtained from thin‐film metal‐insulator‐metal (MIM) samples have often been analyzed qualitatively in terms of the Debye relaxation process. Here we point out several anomalies and discrepancies associated with these analyses. We then go on to develop the theory of ac electrical properties in MIM systems in which Schottky barriers are assumed to exist at the metal‐insulator interface. The resulting capacitance and conductance vs frequency, temperature, and voltage bias are shown to exhibit all the salient features of the observed data, suggesting that such a model is more applicable than the Debye model, at least in the case of the materials reviewed.