Realization of Large-Domain Barium Disilicide Epitaxial Thin Film by Introduction of Miscut to Si(111) Substrate

Abstract

The domain structure of BaSi2 epitaxial films grown on vicinal Si(111) substrates has been studied in order to fabricate high-quality BaSi2 crystals with large domains. The X-ray pole figure measurement shows that the BaSi2 films grown on vicinal substrates as well as the on-axis substrate consist of three epitaxial variants which are equivalent in terms of 60° in-plane rotations, and that one of the variants is dominant in the film grown on the 2°-inclined substrate. The orientation maps produced by electron backscatter diffraction show that the domains with the b axis parallel to the miscut direction are larger than the others in the film grown on the 2°-inclined substrate, while the domain sizes of three variants are found similar in the films grown on the on-axis and 4°-inclined substrates. The possible origin of the large domain formation is discussed with the focus on the initial growth stage observed by atomic force microscopy. Nucleation from the step edge is proposed as the mechanism of the large-domain formation considering the lattice matching to the step edge, while nucleation is suggested to occur at the terrace edges on the 4°-inclined substrate.