Molecular beam epitaxy of BaSi2 thin films on Si(001) substrates

An attempt was made to grow BaSi2 epitaxial films on Si(001) substrates using molecular beam epitaxy. The structure and morphology of the films were investigated using reflection high-energy electron diffraction, X-ray diffraction, electron backscatter diffraction, atomic force microscopy, and transmission electron microscopy. The BaSi2 film grown was a-axis oriented, despite a large lattice mismatch. The measurements indicated that there are two possible epitaxial relationships of BaSi2(100)//Si(001) with BaSi2[010]//Si[110] and BaSi2[001]//Si[110], due to the fourfold symmetry of Si(001). X-ray reciprocal space mapping revealed that the BaSi2 film was almost strain-free. Plan-view transmission electron microscopy clarified the grain size and the existence of grain boundaries in the BaSi2 film. (c) 2012 Elsevier B.V. All rights reserved.