The conductivity mechanism and an improved C−V model of ferroelectric PZT thin film

A dense, homogeneous and crack-free ferroelectric PZT thin film with 〈100〉-preferred orientation was produced using the sol-gel method. The volume fraction α₍₁₀₀₎ of 〈100〉-oriented grains in the PZT film was calculated [α₍₁₀₀₎ ≈ 80%] from XRD of the PZT thin film and powder. The PZT thin film exhibits an open polarization vs. electric field loop and a low leakage current density from 10⁻⁸ A/cm² to 10⁻⁷ A/cm². The electrical conduction data were fit to a Schottky-emission model with deep traps from 100 kV/cm to 250 kV/cm. A modified capacitance model was introduced that adds electrical domain capacitance based on a metal-ferroelectric-metal (MFM) system with Schottky contacts. The model reproduces the observed non-linear capacitance vs. voltage behavior of the film.