Epitaxial Si films grown on lattice matched (La_xY _1-x)O₃/Si (111) structures by molecular beam epitaxy

Abstract

Growth of epitaxial Si epitaxial overlayers on lattice matched (La xY1-x)2O3/Si (LaYO/Si) structures has been investigated by high resolution transmission electron microscopy and reflection high energy electron diffraction, Results indicate that smooth two-dimensional near lattice-matched LaYO (111) films can be grown on Si (111) substrates. However, subsequent Si epitaxial, growth on the LaYO/Si structures nucleates as three-dimensional islands, a consequence of the high energy of the Si overlayer/LaYO interface. We have investigated the effect of growth temperature on the microstructure of the Si overlayers. Higher temperatures resulted in the nucleation of large faceted islands and rough overlayers while lower temperatures result in smaller islands that coalesce at an early stage and produce smoother films. In addition, formation of planar defects in these films is attributed to stacking errors on the {111} facets of initial Si islands with lower temperatures resulting in a higher density of stacking faults and twins.