Growth and structural properties of crystalline LaAlO3 on Si(001)

Crystalline LaAlO3 was grown by oxide molecular beam epitaxy (MBE) on Si (001) surfaces utilizing a 2 ML SrTiO3 buffer layer. This SrTiO3 buffer layer, also grown by oxide MBE, formed an abrupt interface with the silicon. No SiO2 layer was detectable at the oxide-silicon interface when studied by cross-sectional transmission electron microscopy. The crystalline quality of the LaAlO3 was assessed during and after growth by reflection high energy electron diffraction, indicating epitaxial growth with the LaAlO3 unit cell rotated 45 degrees relative to the silicon unit cell. X-ray diffraction indicates a (001) oriented single-crystalline LaAlO3 film with a rocking curve of 0.15 degrees and no secondary phases. The use of SrTiO3 buffer layers on silicon allows perovskite oxides which otherwise would be incompatible with silicon to be integrated onto a silicon platform. (C) 2007 Elsevier B.V. All rights reserved.