A C 1s core level x-ray photoelectron diffraction characterization of substitutional carbon in epitaxial Si1−yCy alloys grown on Si(111) and Si(001)

Epitaxial strained growth of Si1−yCy alloys with rather high C concentrations (y∼1.5%) has been performed on Si(111) and Si(001) using molecular beam epitaxy (MBE) Si evaporation and thermal interaction of the growth surface with a low C2H4 pressure at 500 °C. Carbon contents, determined by secondary ion mass spectrometry, infrared (ir) spectrometry, in situ C 1s and Si 2p x-ray photoelectron spectroscopy measurements and x-ray diffraction (XRD), are being compared. Monocrystalline quality of the epilayers is checked by low energy electron diffraction and x-ray photoelectron diffraction (XPD). As indirectly ascertained by the ir local vibration mode (LVM) and a shifted partially strain induced epilayer diffraction line in the θ-2θ XRD analysis, carbon is accommodated in substitutional sites (Csub) whose local atomic order is investigated for the first time by XPD, C 1s polar angle distributions being measured in different azimuthal directions. As the data reveal, for a C emitter, next nearest neighbor bon...