Negative Differential Resistivity and Positive Temperature Coefficient of Resistivity effect in the diffusion limited current of ferroelectric thin film capacitors

TL;DR

This paper introduces a diffusion-limited current model for ferroelectric thin-film capacitors that explains negative differential resistivity, plateaus at low voltages, and the positive temperature coefficient of resistivity observed in experiments.

Contribution

The paper presents a novel diffusion-limited current model that accounts for previously unexplained phenomena in ferroelectric capacitor leakage currents.

Findings

Explains negative differential resistivity at low voltages.

Accounts for positive temperature coefficient of resistivity in high-voltage regime.

Recovers the diffusion-limited Schottky relationship in the high-voltage regime.

Abstract

We present a model for the leakage current in ferroelectric thin- film capacitors which explains two of the observed phenomena that have escaped satisfactory explanation, i.e. the occurrence of either a plateau or negative differential resistivity at low voltages, and the observation of a Positive Temperature Coefficient of Resistivity (PTCR) effect in certain samples in the high-voltage regime. The leakage current is modelled by considering a diffusion-limited current process, which in the high-voltage regime recovers the diffusion-limited Schottky relationship of Simmons already shown to be applicable in these systems.