Heteroepitaxial growth of InSb on Si(001) surface via Ge buffer layers

InSb was grown on the Si(001), Ge(001) and Ge/Si(001) substrates by the coevaporation of elemental In and Sb sources. The grown films were characterized by AES (Anger electron spectroscopy), optical microscope, XRD (X-ray diffraction), SEM (scanning electron microscope) and ECP (electron channeling pattern), as a function of growth conditions, such as growth temperature and flux ratio of Sb/In. The thickness of grown InSb films was about 0.8-1.2 mu m. In contrast with the direct growth on Si(001) surface, InSb easily grows heteroepitaxially on Ge(001) and Ge/Si(001) substrates, for wide growth conditions. The surface morphology and the crystal quality of the grown films strongly depend on the flux and/or composition ratio of Sb/In. It is found that the optimized flux ratio is about 4.5 to obtain the stoichiometric InSb films with smooth surface at growth temperature of 300 degrees C. However, the XRD spectrum and ECP pattern reveal that better crystal quality is obtained for the In-rich films rather than the stoichiometric films.