Metal-Ferroelectric-Metal structures with Schottky contacts: II. Analysis of the experimental current-voltage and capacitance-voltage characteristics of Pb(Zr,Ti)O3 thin films

A modified model of metal-semiconductor contacts is applied to analyze the capacitance-voltage and current-voltage characteristics of metal-ferroelectric-metal structures. The ferroelectric polarization is considered as a sheet of surface charge situated at a fixed distance from the interface. The presumable high concentration of structural defects acting as active electric traps is taken into account by introducing a deep acceptor-like level. The model is applied on a set of metal-PZT--metal samples with different Zr/Ti ratios, deposited by different methods, and having different thickness, electrode materials, and electrode areas. The concentration of the free carriers, the fixed charge density in the depletion region, the distance between polarization charge and the physical interface, the potential barrier were estimated.