Structural and compositional investigation of yttrium-doped HfO2 films epitaxially grown on Si(111)

Cubic phase yttrium-doped HfO2 (YDH) ultrathin films were grown on Si(111) substrates by molecular beam epitaxy. Thorough structural and morphological investigations by x-ray scattering and transmission electron microscopy reveal that the YDH thin films are epitaxially grown on the Si substrates with (111)(YDH)parallel to (111)(Si) and [10 (1) over bar] YDH parallel to [1 (1) over bar0](Si). The interface between YDH and Si is atomistic sharp and free of interfacial layer. We have also determined the yttrium content of YDH films to be 19% by using anomalous x-ray diffraction (AXD) across Y k edge and angle resolved x-ray photoelectron spectroscopy (AR-XPS). The agreement between the AXD and AR-XPS results manifests that the incorporated Y atoms homogeneously substitute Hf atoms in the crystalline lattice and form a substitutional solid solution. (c) 2007 American Institute of Physics.