Preferential growth of (001)-oriented Bi2SiO5 thin films deposited on (101)-oriented rutile substrates and their ferroelectric and dielectric properties

Ferroelectric thin films are important because of their great potential for use in various electric devices such as ferroelectric random-access memory. It was expected that Bi2SiO5, a Si-containing ferroelectric material, would show improved ferroelectricity by targeting a film with the (001)-orientation (polar-axis) on the substrate. Although there was a narrow process window for the deposition of the (010)/(001)-oriented Bi2SiO5 thin film, it was successfully prepared on a (101)-oriented TiO2 single substrate using the pulsed layer deposition technique. The optimum film deposition conditions and film thickness were found, and in this material, the volume fraction of the (001)-oriented domain reached about 70%. By controlling film orientation to the polar axis, the remanent polarization value of this film was 4.8 μC cm−2, which is the highest value among reported Bi2SiO5.