Silicon carbide(SiC) nano-crystallites are formed by the thermal reaction of C-60 molecules with silicon atoms on Si(0 0 1) and Si(1 1 1) surfaces at 900-1150 degreesC. The surface morphologies and structures of the cubic beta -SiC islands on Si(0 0 1) and Si(1 1 1) are investigated in situ using scanning tunneling microscopy. Comparing to bulk SiC crystals, distinctive atomic structures are formed on the surfaces of the SIC crystallites: a (2 x 3) on SiC(0 0 1) and a (2 root 3x 2 root3)R30 degrees reconstruction on SiC(1 1 1). In addition, monatomic and multiatomic steps are observed.