Crystalline and Polarization Orientation Control of BaTiO₃ Thin Films on SrTiO₃ -buffered Si for Electro-Optic Applications

Recent research has shown that BaTiO₃ thin films epitaxially grown on Si are capable of a large electro-optic response via the Pockels effect crucial for fabricating efficient phase modulators in silicon-integrated photonics. However, the orientation dependence of BaTiO₃ for most films yields a dead layer (a region of the film with low electro optic response) for most device geometries. We report on a Si-on-insulator integrated film stack including a buffer layer that effectively negates this region from existing. The film’s quality is confirmed with crystalline characterization and electro-optics measurements showing a response of about 85 pm/V which indicates that this system is a beneficial addition to the field of Si photonics.