Characterization of epitaxial Si 1− yC y layers on Si(0 0 1) grown by gas-source molecular beam epitaxy

Abstract

Epitaxial Si 1− y C y layers were grown by gas-source molecular beam epitaxy using Si 2H 6 (100%) and C 2H 2 (1% C 2H 2 in 99% He) between substrate temperatures of 600 to 700°C. Epitaxial Si 1− y C y films were obtained using C 2H 2 flow rates ranging from 0 to 1.0 sccm. Substitutional C atoms in the films were detected as the C local vibration mode (607 cm −1) in Raman and Fourier transform infrared absorption spectroscopy. The formation of the Si 1− y C y alloys was also confirmed by θ/2 θ measurements of X-ray diffractometry (XRD). The reciprocal lattice space map indicated the pseudomorphic growth of the Si 1− y C y layer on Si(0 0 1). The substitutional C content ( C s) was estimated using Vegard’s law and XRD data with a maximum C s of 0.96% obtained in a sample grown at 675°C. From the characterization of Si 1− y C y films annealed at temperatures between 700°C and 900°C, it was found that the thermal stability of the film strongly correlates with the initial C s content.