Hexagonal and cubic SiC thin films on SiC deposited by solid source MBE

Epitaxial growth of SiC on SiC was realized between 900 and 1100 degrees C by means of solid-source molecular beam epitaxy. In general, our results show that the growth mode is strongly influenced on the surface stoichiometfy. In case of Si-stabilized surfaces, showing 3-fold superstructures, films grow layer-by-layer via two-dimensional nucleation even at relatively low temperatures (<1000 degrees C). RHEED investigations of the epitaxial growth on 3C-SiC(100) show that a layer by layer growth is achieved at T>925 degrees C and R<100 nm h(-1). The activation energy of nucleation was determined to be 5.3 eV. The film structure was found to be dependent on the deposition mode. In the case of continuous deposition the films consist of a mixture of the cubic and hexagonal polytypes. The films grown by an alternating flux supply controlled to an atomic level using (root 3x root 3)- and (1 x 1)-surface superstructures were dominantly of 6H-SiC. In case of the Si-rich (3 x 3)-superstructure actually the cubic polytype has been grown. Therefore, we assume that the formation of a certain superstructure stabilizes the nucleation of a special polytype. (C) 1997 Elsevier Science S.A.