Local field inhomogeneity and ferroelectric switching dynamics in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Hf</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>Zr</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> thin films
Myeong Seop Song, K. C. Lee, Jin-Beom Choi, Kyoungjun Lee, Seung Chul Chae
Abstract
We report on the inhomogeneity of the internal bias according to the Zr alloy concentration confirmed by the ferroelectric switching dynamics of ${\mathrm{Hf}}_{1\ensuremath{-}x}{\mathrm{Zr}}_{x}{\mathrm{O}}_{2}$ thin films. The analytic model for the internal bias was considered in terms of the dipole-dipole interaction accompanied by Zr concentration variation. The ferroelectricity and switching dynamics of ${\mathrm{Hf}}_{1\ensuremath{-}x}{\mathrm{Zr}}_{x}{\mathrm{O}}_{2}$ thin films were investigated using conventional electrical measurements and local piezoresponse microscopy. Analysis of static and dynamic polarization reversal revealed a correlation between the activation field for polarization switching and Zr concentrations through the variation in local ferroelectric coercivity and the characteristic ferroelectric switching time. The spatially inhomogeneous local built-in electric field was attributed to the defect interaction in the ${\mathrm{Hf}}_{1\ensuremath{-}x}{\mathrm{Zr}}_{x}{\mathrm{O}}_{2}$ thin films.