Growth of Ge_1-xC_x alloys on Si by combined low-energy ion beam and molecular beam epitaxy method

A combined ion beam and molecular beam epitaxy (CIBMBE) method was applied for the deposition of a Ge_1-xC_x alloy on Si(100) using a low-energy (50-100 eV) C⁺ ion beam and a Ge molecular beam. Metastable Ge_1-xC_x solid solutions were formed up to x = 0.047, and the CIBMBE method was shown to have a very high potential to grow metastable Ge_1-xC_x alloys. It was also revealed that the sticking coefficient of C⁺ ions into Ge was approximately 28% for E_i = 100 eV and approximately 18% for E_i = 50 eV. Structural characterization suggests that the deposited films are single crystals grown epitaxially on the substrate with twins on {111} planes. Characterization of lattice dynamics using Raman spectroscopy suggested that the deposited layers have a small amount of ion irradiation damage.