Fabrications of nanoscale structures of C-60 crystals on GaAs substrates are successfully achieved by selective area molecular beam epitaxy. The grown structures are examined by scanning electron and atomic force microscopies. The {100} and {110} facets appear at the side boundaries of the C-60 crystals. The surface morphology of C-60 crystals grown on GaAs (111)B is much smoother than that grown on GaAs (001). Good crystalline properties of C-60 films grown on GaAs (111)B are also confirmed by x-ray diffraction phi (phi) scan measurement. During C-60 deposition, C-60 molecules landing on SiO2 mask either evaporate or migrate to the open area enhancing the growth rate at the edges of the area. The mean diffusion length of C-60 molecules on SiO2 mask at 200 C is evaluated to be 200-300 nm. The C-60 crystals grown on GaAs.(001) with narrow open area (100-200 nm) have a fourfold symmetry, indicating that the epitaxial orientation of these C-60 crystals is [001]. This result should be compared with the [111] orientation observed in planar or wide area growth. (c) 2006 American Vacuum Society.