Title

Influence of space-charge on hysteresis loop characteristics of ferroelectric thin films

Document Type

Article

Publication Date

2-2008

Publication Source

IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society

Abstract

Hysteresis loops of Pb(Zr, Ti)O3 (PZT) thin films obtained by using a Sawyer-Tower (ST) circuit are affected by many factors. This paper investigated the influence of space charge on the hysteresis loop of thin-film ferroelectrics, based on the model that polarization consists of two parts: linear and switching polarization. It is found that the space charge affects both the shape and offset of the ideal hysteresis loop. Further investigation shows that the practical hysteresis loop has a close relationship with the equivalent ST circuit parameters: the leakage resistance of the FE film, the equivalent input impedance of the measurement equipment, the signal source, and other similar parameters. The normally assumed symmetric hysteresis loop without any offset is obtained with an ST circuit when the output becomes stable. The hysteresis loop obtained at the initial stage of applied signal depends on the initial status of the FE film, and remnant polarization causes an initial offset that gradually disappears.

Inclusive pages

286 - 292

ISBN/ISSN

0885-3010

Publisher

IEEE

Volume

55

Issue

2

Peer Reviewed

yes

Keywords

dielectric hysteresis;dielectric polarisation;ferroelectric switching;ferroelectric thin films;lead compounds;space charge;PZT thin films;Pb(ZrTi)O3;Sawyer-Tower circuit;equivalent input impedance;ferroelectric thin films;hysteresis loop;leakage resistance;linear polarization;remnant polarization;space charge effects;switching polarization;Electrical resistance measurement;Ferroelectric materials;Hysteresis;Impedance;Iron;Polarization;Shape;Space charge;Thin film circuits;Transistors