First stages of low temperature and low pressure carbonization of Si(001) in acetylene"

The thermal growth of 3C-SiC films at 820 degrees C in acetylene (chosen among other hydrocarbons because of its high reactivity with Si) was performed and the resulting films were analyzed by nuclear reaction analysis (NRA), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), Films were grown on clean single domain 2 x 1 reconstructed Si (0 0 1)vicinal surfaces either in natural (C2H2) or in 99% deuterium enriched (C2D2) acetylene under 2 x 10(-6) Torr, In order to characterize the electronic structure and the short range order of the films, XPS and its by-product X-ray photodiffraction (XPD) were performed in situ in an analysis chamber connected to the preparation chamber, The growth kinetics was followed by measuring, ex situ, the amount of incorporated carbon using the C-12(d,p)C-13 reaction at 970 keV, while for determining the hydrogen incorporation in the films the D(He-3,p)He-4 reaction at 700 keV was used. Also ex situ, the film morphology was followed by SEM as the thickness of the layer increased. By using these complementary techniques, phenomena like I-I incorporation, C in-diffusion and 3C-SiC nucleation have been evidenced at the very beginning of the growth (amount of C-12 incorporated in the films smaller than 10(16) atoms/cm(2)). Besides, it was observed that the imperfect coalescence of 3C-SiC nuclei determine the morphology of films grown during longer times.