Equivalent circuits representing (a) an ideal polymer MIS capacitor and (b) modified to account for time constant dispersion in the bulk polymer. Additional components are required in parallel with to describe the effects of (c) a discrete set and (d) a distribution of interface states.
Frequency dependence of (a) the measured capacitance and (b) the loss of an MIS capacitor after the fifth anneal stage, showing device depletion at more positive applied voltages. The Maxwell-Wagner dispersion is clearly visible. A weak feature due to interface states can also be seen at low frequencies. The inset in (b) shows the structure of the device with its guarded top gold electrode.
(a) Capacitance-voltage characteristics measured at room temperature at after each anneal stage and (b) the calculated doping densities plotted as a function of measurement frequency.
Loss-voltage characteristics measured at after each anneal stage.
Effect of measurement frequency on the loss-voltage characteristics of a MIS capacitor after the fifth anneal.
Experimentally measured admittance (points) and theoretical fits (continuous lines) to the weak-depletion-region regime (shallow trap case) using the equivalent circuits in Figs. 1(b) and 1(d) and the parameters in Table I.
Experimentally measured admittance (points) and theoretical fits (continuous lines) to the strong-depletion-region regime (deep trap case) using the equivalent circuits in Figs. 1(b) and 1(d) and the parameters in Table II.
Evolution of the frequency dependence of (a) capacitance and (b) loss measured at applied voltages corresponding to the loss peak maxima associated with the deep set of interface states in Fig. 4, i.e., the features appearing at positive voltages.
Parameters used to provide the best fit to the experimental data in Fig. 6 relating to the shallow traps after the fifth anneal.
Parameters used to provide the best fit to the experimental data in Fig. 7 relating to the deep traps after the fourth anneal. Also given is the calculated band bending .
Parameters giving the best fit to the experimental data in Fig. 8. Also presented are the corresponding doping densities and band bending.
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