Simulation of the capacitance-voltage characteristics of a ferroelectric material

The parameters of a ferroelectric material without initial polarization are simulated. The ferroelectric material is doped with a shallow-level impurity. One of the contacts is represented by the Schottky barrier, and the other contact is ohmic. The variations in the electric field, potential, polarization, and permittivity through the depth of the space charge layer are calculated. It is shown that the value of the permittivity in low fields, εeff0, can be determined from the parameters of the experimental hysteresis loop. In low fields (E < 105 V/cm), the permittivity depends on the field only slightly. Therefore, for (E < 105 V/cm), the value of εeff0 can be used as the average value of εeff in processing the experimental data. The calculation of the dependence of the reverse capacity squared on the potential-barrier height shows that, at low voltages, this dependence is nearly linear. This allows the concentration of shallow dopants to be determined from the dependence. The thickness of the space charge layer and the polarization near the contact are calculated as functions of the potential-barrier height. The results of the simulation can be used in processing the experimental data.