In this work for the first time a comprehensive research of (Si 1-x C 1-y )Ge x+y thin films epitaxially grown on Si (111) substrates by solid source molecular beam epitaxy are presented. The layers were grown at substrate temperatures ranging from 900 °C to 1040 °C with a growth rate of 0.6 nm/min. They were analysed by atomic force microscopy, scanning electron microscopy, X-ray diffraction, Auger electron spectroscopy, secondary ion mass spectroscopy and transmission electron microscopy. The structural analysis revealed that the grown epitaxial layer consists of the cubic polytype. A maximum Ge incorporation of 0.16% was achieved in epitaxial layers grown at 900 °C. It was obtained that the Ge concentration decreases with increasing growth temperature.