Epitaxial Relations in Lattice-Matched (Ca, Sr)F2 Films Grown on GaAs{111} and Ge(111) Substrates

Abstract

Epitaxial relations in lattice matched Ca_0.42Sr_0.58F₂ films grown on GaAs(111), (1̄1̄1̄) and Ge(111) substrates were investigated by 2-MeV ⁴He⁺ ion channeling and backscattering measurements. It was found that the epitaxial films on GaAs have an orientation indentical to that of substrates (type A), whereas those on Ge mainly exhibit an orientation rotated by 180° about the surface normal axis (type B), though both substrates have nearly the same lattice constant.