Lateral force microscopy investigations of the crystallization of SrBi2Ta2O9 thin films

A lateral force microscope (LFM) was used for studying the surface morphologies of SrBi2Ta2O9 thin films with varying post-annealing temperature. Specimens were prepared onto platinized silicon wafers by the sol-gel method and post-annealed at 600-800 degrees C. Non-ferroelectric matrix phases were found for specimens annealed below 700 degrees C, which were confirmed by the measurement of X-ray diffraction (XRD) patterns. The friction coefficients between the surface of ferroelectric grain and non-ferroelectric matrix, and the silicon nitride tip, were determined from the line profile of the LFM images. The measured coefficients of friction for a tip on grain and matrix are 0.19 +/- 0.08 and 0.28 +/- 0.08, respectively. In the LFM images, the matrix phases decreased with increasing post-anneal temperature and the surfaces of the specimens annealed above 700 degrees C were filled with SET grains which were consistent with the XRD results. Ferroelectricities of these specimens were confirmed by the measurement of polarization held hysteresis loops. (C) 1998 Elsevier Science S.A. All rights reserved.