Microstructural analysis and electro-optic properties of thick epitaxial <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>BaTiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math> films integrated on silicon (001)
Marc Reynaud, Zuoming Dong, Hyoju Park, Wente Li, Agham Posadas, Jamie H. Warner, Daniel Wasserman, Alexander A. Demkov
Abstract
Recent advances in epitaxial oxide deposition have enabled the fabrication of thick films of ferroelectric perovskite ${\mathrm{BaTiO}}_{3}$ capable of providing a robust electro-optic response via the Pockels effect in silicon photonic devices. We report a microstructure analysis of such films integrated on Si(001) by molecular beam epitaxy, showing how the crystallographic and polarization orientation change as a function of thickness. The measured electro-optic properties of the film correlate well with the microstructural analysis and demonstrate the potential of Si-integrated ${\mathrm{BaTiO}}_{3}$ for silicon photonics. An effective Pockels coefficient of up to 268 pm/V has been demonstrated in 110-nm-thick films in transmission measurements and 352 pm/V in waveguide measurements.