Growth of tantalum oxide and lithium tantalate thin films by molecular beam epitaxy

Abstract

Thin films of tantalum oxide and lithium tantalate have been grown on Si (100) and Si (111) substrates by molecular beam epitaxy. At the tantalum deposition rates of 0.3 Å s −1 the use of molecular oxygen in the growth process yielded only partially oxidized films. A complete in situ oxidation of the grown layers has been achieved by the use of an ECR plasma source. Tantalum oxide thin films were amorphous in structure due to the low substrate temperature. Lithium tantalate thin films showed a stoichiometric composition and were fully oxidized in situ as proved by quantitative XPS analysis. X-ray diffraction revealed a preferentially oriented polycrystalline structure with the (102) planes of LiTaO 3 being parallel to the (100) planes of Si.