Heterolayered PZT thin films of different thicknesses and stacking sequence

The effects of stacking sequence and thickness toward the texture and electrical properties of heterolayered PbZr (x) Ti1-x O-3 (PZT) films, consisting of alternating PbZr0.7Ti0.3O3 and PbZr0.3Ti0.7O3 layers, have been studied. Thickness dependence is observed in the ferroelectric and dielectric behavior of the heterolayered PZT films whereby the remanent polarization (P (r)) and relative permittivity (epsilon) increase with thickness, while coercive field (E (c)) decreases. When baked at 500 A degrees C and thermally annealed at 650 A degrees C, the heterolayered PZT films regardless of their stacking sequence exhibit perovskite phase with (001)/(100) preferred orientation. Interestingly, the stacking sequence of the heterolayered PZT films dictates the morphology of the films which eventually affects the ferroelectric and dielectric performance. The heterolayered PZT film with PbZr0.7Ti0.3O3 as the first layer (heterolayered PZ(70)T(30) film) exhibits a large grain size in the range of 1-3 mu m and shows superior properties as compared to the heterolayered PZT films with PbZr0.3Ti0.7O3 as the first layer (heterolayered PZ(30)T(70) film), which exhibits a much smaller grain size. From the sub-switching field measurement according to the Rayleigh law, there appears a lower concentration or mobility of domain walls in the small-grained heterolayered PZ(30)T(70) films.