Electron Backscatter Diffraction Analysis for Polarization of SrBi2(Ta,Nb)2O9 Ferroelectric Capacitors in Submicron Small Area

概要

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We investigate the size and crystal orientation of each small grain of ferroelectric SrBi2(Ta,Nb)2O9 (SBTN) films within very small areas by an electron backscatter diffraction (EBSD) analysis technique. The obtained map of the grains reveals that the size of $c$-axis-oriented grains increases as the average grain size of the films increases. On the other hand, the size of $a$-axis-oriented grains, each of which has a finite remnant polarization normal to the films, is almost unchanged. The area fraction of the $a$-axis-oriented grains is in good agreement with the measured polarizations of ferroelectric capacitors with different average grain sizes. This result implies that an increase in the number of relatively small $a$-axis-oriented grains is effective for increasing the total polarization of the ferroelectric films. The demonstrated analysis technique is very useful for the precise design of future high-density ferroelectric random access memories (FeRAMs) with very small capacitor structures, each of which consists of only a few grains.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2008-01-25