Epitaxial Growth of Silicon on CoSi₂ (001)/Si (001)

Abstract

Epitaxial Si layers have been grown under a variety of growth conditions on CoSi₂ (001) by molecular beam epitaxy (MBE). The structural properties of the Si overgrowth were studied by in-situ Reflection High Energy Electron Diffraction (RHEED), as well as ex-situ MeV⁴He⁺ ion channeling and High Resolution Transmission Electron Microscopy (HRTEM). Strong influences of the CoSi₂ surface reconstruction on the Si overgrowth have been observed. RHEED studies show islanding growth of Si on the CoSi₂ (001) (3/√2 × √2)R45 reconstructed surface, but smooth growth of Si on the CoSi₂ (001) {√2 × √2)R45 reconstructed surface, under the same growth conditions. The growth of Si on thin layers of CoSi₂ (2nm-6nm) with (√2 × √2)R45 reconstructed surface at 460°C results in high crystalline quality for the Si top layer, as indicated by good channeling minimum yield (Xmin < 6%), but cross-sectional TEM shows that the CoSi₂ layers are discontinuous. We also report preliminary results on Si grown on a 2 × 2 reconstructed CoSi₂ (001) surface.