Crystalline texture analyses of sputtered BiFeO3 thick films on Si with a large polarization

Abstract

In our work last year (H. Zhu et al., Rhombohedral BiFeO 3 thick films integrated on Si with a giant electric polarization and prominent piezoelectricity, Acta Materialia 200 (2020) 305–314), it was demonstrated that the rhombohedral-like, (110)-textured BiFeO 3 thick films (∼2 μm) sputter-deposited at 450 °C and 500 °C exhibited ultrahigh polarizations of P r ∼ 115 μC/cm 2 and 135 μC/cm 2 , respectively. However, it is not sufficient to explain these ultra-high polarizations by a preferential growth mechanism and the effect of a moderate compressive strain. To further clarify the polarization enhancement of the films, the texture characteristics of these BFO thick films were quantitatively analyzed by fitting the rocking curves and pole figures to the March-Dollase model. The results showed that, in addition to the (110)-textured growth of a BFO thick film under a moderate compressive strain, the minority non-(110)-textured grains also contributed to the enhancement of the total polarization. Our study demonstrates that, the ultra-high polarizations of our BFO thick films can be well explained by adding the contribution from non-textured grains to the preferential growth of the film under a compressive strain. • (110)- and (100)-textured BFO thick films were sputtered deposited on platinized Si substrates. • The films’ texture chracteristics were quantitatively analyzed based on the March-Dollase fuction. • The contributions of textured and non-textured grains to polarization enhancement were mainly discussed. • An achievement of unusually large polarization of BFO thick film can be well explained.