Si-Integrated BaTiO<sub>3</sub> for Electro-Optic Applications: Crystalline and Polarization Orientation Control
Marc Reynaud, Huaixun Huyan, Chaojie Du, Wente Li, Agham Posadas, Xiaoqing Pan, Alexander A. Demkov
Abstract
Recent research has demonstrated that BaTiO 3 epitaxially grown on Si is capable of a large electro-optical response via the Pockels effect crucial for fabricating efficient phase modulators in integrated silicon photonics. However, the typical crystallographic orientation evolution of epitaxial BaTiO 3 on SrTiO 3 -buffered Si yields a dead layer (a region of the film with a low electro-optic response) for most device geometries. We report on a Si-on-insulator-integrated film stack incorporating a MgO buffer layer that effectively alleviates this problem. The film quality is confirmed with crystallographic characterization; electro-optic measurements yield an effective Pockels coefficient of 119 pm/V for a 100 nm thick film.