Ferroelectric and piezoelectric responses of (110) and (001)-oriented epitaxial Pb(Zr0.52Ti0.48)O3 thin films on all-oxide layers buffered silicon

• We fabricate all-oxide, epitaxial piezoelectric PZT thin films on Si.
• The orientation of the films can be controlled by changing the buffer layer stack.
• The coherence of the in-plane orientation of the grains and grain boundaries affects the ferroelectric properties.
• Good cycling stability of the ferroelectric properties of (001)-oriented PZT thin films. The (110)-oriented PZT thin films show a larger d33,f but smaller d31,f than the (001)-oriented films.

Epitaxial ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT) thin films were fabricated on silicon substrates using pulsed laser deposition. Depending on the buffer layers and perovskite oxide electrodes, epitaxial films with different orientations were grown. (110)-oriented PZT/SrRuO3 (and PZT/LaNiO3) films were obtained on YSZ-buffered Si substrates, while (001)-oriented PZT/SrRuO3 (and PZT/LaNiO3) were fabricated with an extra CeO2 buffer layer (CeO2/YSZ/Si). There is no effect of the electrode material on the properties of the films. The initial remnant polarizations in the (001)-oriented films are higher than those of (110)-oriented films, but it increases to the value of the (001) films upon cycling. The longitudinal piezoelectric d33,f coefficients of the (110) films are larger than those of the (001) films, whereas the transverse piezoelectric d31,f coefficients in the (110)-films are less than those in the (001)-oriented films. The difference is ascribed to the lower density (connectivity between grains) of the former films.

The cross sections show a very dense structure in the (001)-oriented films (c,d), while an open columnar growth structure is observed in the case of the (110)-oriented films (a,b). The (110)-oriented PZT films show a significantly larger longitudinal piezoelectric coefficient (d33,f), but smaller transverse piezoelectric coefficient (d31,f) than the (001) oriented films.Figure optionsDownload as PowerPoint slide