Abstract :
Hydrogen-free amorphous carbons (a-C) have been prepared on mirror-polished Si(1 1 1) wafers through thermally evaporated C60 with
simultaneous bombardments of Ne+ ions. The time evolution of film surfaces has been characterized by atomic force microscopy (AFM) at two
temperatures of 400 and 700 8C, respectively. Based on the topography images and the root-mean-square (rms) roughness analysis, it is found that
the a-C surfaces present roughening growth at the initial stage. With increasing growth time, the cooperative nucleation of the islands and pits
appears on the surfaces, suggesting three-dimensional growth, and then they continue to evolve to irregular mounds at 400 8C, and elongated
mounds at 700 8C. At the steady growth stage, these surfaces further develop to the structures of bamboo joints and ripples corresponding to these
two temperatures, respectively. It is believed that besides ion sputtering effect, the chemical bonding configurations in the amorphous carbon films
should be taken into considerations for elucidating the surface evolutions.
