Debye-like dielectric dispersion properties of evaporated silicon oxide films at very low frequencies

Dielectric dispersion properties of evaporated silicon oxide films sandwiched between Al electrodes are reported for the frequency range from 0.1 Hz to 20 kHz and the results are analysed by comparing them with the ETSC (electrically excited thermally stimulated current) and the DC current-voltage characteristics. It is shown that the total conductance measured by the AC bridge method is constructed of DC and AC conductivities, as expressed by the empirical relation sigma ( omega )= sigma dc + sigma ac ( omega ). Only the AC conductivity is related to the dielectric dispersion properties, which are Debye-like. The activation energy and the frequency factor of the relaxation frequency are in good agreement with those deduced from the ETSC results. At a frequency moderately higher than the relaxation frequency, the AC conductivity obeys the empirical relation sigma ac varies as omega 0.66. The frequency range over which the empirical relation holds is about four decades, which is much narrower than the results of Frost and Jonscher (1975).