Microstructural Evolution of Co2GaAs Thin Film on GaAs Substrate

Abstract

ABSTRACTInterfacial reactions and epitaxial growth of the microstructure between cobalt thin film and (100)-oriented GaAs substrate have been studied, using X-ray diffraction, transmission electron microscopy and EDS analysis. Cobalt thin films were deposited by e-beam evaporation, and were subsequently annealed at 400 °C.The reaction layer evolved due to the annealing was identified as the ternary phase, Co2GaAs, that was grown epitaxially on the substrate. The new orientation relationship between Co2GaAs and GaAs substrate was found as <110>Co2GaAs // <100>GaAs and {001}Co2GaAs // {011}GaAs. These results can be well explained upon matching the unit cells of Co2GaAs and GaAs. Upon the annealing at 600°C, the Co2GaAs phase is usually decomposed to stable binary phases, CoGa and CoAs.