Ferroelectric Properties of Bi_3.25La_0.75Ti₃O₁₂ Thin Films Crystallized inDifferent N₂/O₂ Ambients

Bi_3.25La_0.75Ti₃O₁₂ (BLT) ferroelectric thin films are deposited by sol-gel method and annealed for crystallizaion in total 1sccm N₂/O₂ mixed gas with various ratio at 750°C for 30min. The effect of crystallization ambient on the structural and ferroelectric properties of the BLT films is studied. The growth direction and grain size of BLT film are revealed to affect ferroelectric properties. After the BLT film is annealed in 20% O₂, the largest P_r value is obtained, which is ascribed to an increase of random orientation and large grain size. The fatigue property is improved with the concentration of oxygen in the ambient increasing, which is ascribed to annealing in the ambient with high concentrated oxygen adequately decreasing the defects related to lack of oxygen.