Capacitance of Thin-film Ferroelectrics under Different Drive Signals

Document Type

Article

Publication Date

9-2009

Publication Source

IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society

Abstract

Thin-film ferroelectric capacitance can be obtained by 2 different methods. Capacitance obtained using the derivative of its hysteresis loop is related to large applied signals and can be called the large-signal capacitance. Capacitance measured directly with a small, applied ac signal together with a slow changing dc bias is called the small-signal capacitance. This paper investigated the voltage dependence of the large- and small-signal capacitances. Measurements show that the large-signal C-V curve of thin-film ferroelectrics has much sharper peaks and higher peak values than the small-signal C-V curve. Analyses based on the Landau-Khalatnikov model shows that practical small-signal capacitance is closer to the ideal capacitance. However, its C-V curve has clearance areas around the coercive voltage, and the polarization switching is not reflected in the small-signal capacitance. This causes the peaks of small-signal C-V curves to be lower than that of large-signal C-V curves.

Inclusive pages

1861 - 1867

ISBN/ISSN

0885-3010

Publisher

IEEE

Volume

56

Peer Reviewed

yes

Issue

9

Keywords

capacitance;dielectric hysteresis;dielectric polarisation;ferroelectric coercive field;ferroelectric switching;ferroelectric thin films;Landau-Khalatnikov model;coercive voltage;hysteresis loop;polarization switching;thin-film ferroelectric capacitance;voltage dependence;Capacitance measurement;Capacitance-voltage characteristics;Ferroelectric materials;Hysteresis;Polarization;Transistors;Voltage

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