Reflection high-energy electron diffraction and low energy electron diffraction studies of the homoepitaxially grown diamond (111) and (001) surfaces

We have investigated the surface morphology and crystallinity of homoepitax ially grown (111) and (001) diamond by reflection high-energy electron diff raction (RHEED) and low energy electron diffraction (LEED). In the smoothes t C(001)-2 x 1/1 x 2 surface, both the RHEED and LEED patterns show half-or der diffraction beams which are characteristically observed as the reconstr ucted surface structures. Caution has to be exercised when judging the stru cture of a C(111) surface from a LEED (1 x 1) pattern, because its observat ion can encompass surface morphologies ranging from single-crystal to polyc rystalline diamond. In contrast, surface roughness has a dramatic effect on the RHEED pattern. The RHEED patterns of the smoothest C(111)-1 x 1 surfac e, grown at 690 degrees C, indicate that the surface smoothness is thought to be the closest to the ideally flat surface compared with previously repo rted homoepitaxial C(111) surfaces. (C) 1999 Elsevier Science S.A. All righ ts reserved.