3C-SiC epitaxial crystal growth was carried out by repeated cycles of Si MBE deposition at room temperature followed by a carbonization under C2H4 and annealing at 900degreesC. This was done on a 3 x 3 reconstructed, well oriented, Si terminated 6H-SiC face. The surface was chemically and crystallographically controlled in situ by photoemission and LEED both during the cleaning procedure and witl-tin any growth sequence. By X-ray photoelectron diffraction and by transmission electron microscopy and diffraction, the 16 nm formed epilayer was characterized as a single 3C-SiC phase. A significant part of the cross-section image exhibits moire fringes whose periodicity (7.5 Angstrom) is three time the d(1) (1 1) reticular distance of the 3C-SiC monocrystal. This is attributed to the superimposition of {1 1 1} twinned domains, a consequence of two equiprobable orientation possibilities for 3C growth onto the hexagonal substrate. The formations of the 15R or the hypothetical 9R polytypes could be ruled out thanks to the electron diffraction patterns. (C) 2002 Elsevier Science B.V. All rights reserved.