Orientation control of a seeding layer and its effect on structure, ferro- and piezoelectric properties of sol-gel derived Bi^sub 3.15^Nd^sub 0.85^Ti^sub 3^O^sub 12^ thin films

We report on the orientation control of a seeding layer for sol-gel derived Bi^sub 3.15^Nd^sub 0.85^Ti^sub 3^O^sub 12^ thin films by optimizing the layer thickness and processing parameters including annealing temperature and time. A 75-nm-thick seeding layer with (100) preferential orientation can be obtained on SiO2/Si substrate by annealing at 560 °C for 3 min. The Bi^sub 3.15^Nd^sub 0.85^Ti^sub 3^O^sub 12^ thin film grown on this optimized seeding layer exhibits a much higher relative intensity of (200) X-ray diffraction peak, which in turn results in more squared P-E hysteresis loops, larger remanent polarization (2P ^sub r^ ~ 62 [mu]C/cm^sup 2^) and piezoelectric coefficient (d ^sub 33^ ~ 74 pm/V) compared to the film without the optimized first layer prepared using the conventional sequential layer annealing method.[PUBLICATION ABSTRACT]