Synthesis of SiC on Si(111) at moderate temperatures by supersonic C-60 beams

We have developed a novel approach to the synthesis of SiC on clean Si substrates in ultra high vacuum (UHV), taking advantage of the features offered by a supersonic beam of C-60. The kinetic energy, ranging from 0.5 up to 60 eV, is much higher than that of standard evaporation techniques (about 0.05 eV). We show that kinetic activation allows the formation of Si-C bonds even at substrate's temperatures lower than 800 degreesC. Films have been grown on the Si(111)-7 x 7 surface, at two different kinetic energies of the C-60 supersonic beam (5 and 20 eV) and at a substrate temperature as low as 750 degreesC. They have been characterized by Auger electron spectroscopy (AES), low energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) and UPS techniques. Electronic and structural properties of films can be controlled by the beam parameters. SiC films synthesized with precursors at 20 eV of kinetic energy are ordered and give rise to good LEED diffraction patterns.