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 (chos en among other hydrocarbons because of its high reactivity with Si) wa s performed and the resulting films were analyzed by nuclear reaction analysis (NRA), X-ray photoelectron spectroscopy (XPS), and scanning e lectron 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 ord er of the films, XPS and its by-product X-ray photodiffraction (XPD) w ere performed in situ in an analysis chamber connected to the preparat ion chamber, The growth kinetics was followed by measuring, ex situ, t he amount of incorporated carbon using the C-12(d,p)C-13 reaction at 9 70 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 increase d. By using these complementary techniques, phenomena like I-I incorpo ration, C in-diffusion and 3C-SiC nucleation have been evidenced at th e very beginning of the growth (amount of C-12 incorporated in the fil ms smaller than 10(16) atoms/cm(2)). Besides, it was observed that the imperfect coalescence of 3C-SiC nuclei determine the morphology of fi lms grown during longer times. (C) 1998 Elsevier Science B.V.