SCANNING-TUNNELING-MICROSCOPY STUDY OF ANTIPHASE BOUNDARIES ON THE (001) SURFACE OF HOMOEPITAXIAL DIAMOND FILMS

Homoepitaxial diamond films have been studied using scanning tunneling microscopy. Boron-doped films were grown on diamond (001) substrates by microwave plasma assisted chemical vapor deposition. Surface morpho logy showed a dimer-type 2X1 reconstructed surface structure with anti phase boundaries on each domain. Single step edges with inequivalent s hape were along the (110) directions. Single steps where dimer rows on the upper terrace are normal to the step edge are ragged and the step s where dimer rows are parallel to the step edge are straight, indicat ing that the steps have different formation energies. To our knowledge , the antiphase boundaries are to be observed for the first time on a homoepitaxially grown diamond (001) surface. Atomic images revealed th at two different types of antiphase boundaries run parallel to or perp endicular to the dimer rows where dimer rows shift by only one lattice constant of the diamond (001) surface.