Film growth and surface reactions of C-60 on Si(100)H(2x1)

High-resolution electron-energy-loss spectroscopy (HREELS) has been used to characterize C-60 films up to 4 monolayers thick grown at room temperature on hydrogen-terminated Si(100). Our results show that compared with C-60 films on clean Si(100) surfaces a considerably higher degree of order in the as-deposited films is achieved. At low coverages the observed C-60 vibrational modes and the Si-H vibrations of the substrate are essentially unshifted, indicating a van der Waals-type interaction between C-60 and Si(100)H(2x1). After annealing at 450 K the film order is substantially increased. Annealing at 600 K results in desorption of the C-60 multilayers and a hydrogen-transfer reaction from the surface to the adsorbed monolayer molecules. When annealing the sample at 800 K, the remaining surface terminating hydrogen desorbs and evidence for a change in the C-60 bonding configuration is found. Finally, flashing the sample at 1300 K leads to the formation of silicon carbide.