Effect of Annealing Temperature on Properties of Barium Zirconium Titanate Thin Films Deposited by Sol-Gel Method

With inorganic salts as the main raw material, the BaZr0.2Ti0.8O3 thin films were prepared on the Pt/Ti/SiO2/Si substrates by sol-gel method. The films were annealed at 600, 700, 800, 900, 1000 degrees C for 30 min in oxygen. X-ray diffraction shows that the BZT films start to crystallize at 600 degrees C, but crystallization basically completed at 700 degrees C and the crystal structure of the films belongs to tetragonal phase. Analyzing the morphology by scanning electron microscopy, it was found that the film structure is dense, and with less crack and larger grains when the annealing temperature is 900 degrees C; while above this temperature obvious polarization versus electric voltage (P-V) hysteresis loop was observed in BaZr0.2Ti0.8O3 films. When the annealing temperature is 1000 degrees C the remnant polarization (2P(r)) and the coercive field (2E(C)) of BaZr0.2Ti0.8O3 films obtained from the hysteresis loop are 1.7 mu C/cm(2) and 6.7 kV/cm, respectively.