Adsorption and thermal reaction of C on Si 111/- 7=7/and 70 Si 100/- 2=1/surfaces: comparison with C60

We report here the measurements of vibrational excitation spectra and the temperature dependence of C70 molecules adsorbed on Si 111.- 7=7.and Si 100.- 2=1.surfaces using high-resolution electron-energy-loss spectroscopy. It is found that a strong interaction of the C70 molecule with the Si 100.surface is induced after annealing at 873 K and that the C70 cage is easier to decompose on that surface. SiC films are formed at 1273 K and 1073 K on the Si 111.- 7=7. and Si 100.- 2=1.surfaces, respectively. Moreover, the formation temperature of 1073 K is lower by 50 K than that of the SiC film from C60 on a Si 100.- 2=1.surface. We discuss the reactivity and the formation temperature of SiC films in terms of the interaction of C70 with the substrates. q1999 Elsevier Science B.V. All rights reserved.