Surface morphology of homoepitaxially grown (111), (001), and (110) diamond studied by low energy electron diffraction and reflection high-energy electron diffraction

The surface morphology and crystallinity of homoepitaxially grown (111), (0 01), and (110) diamonds were comparatively investigated by using low-energy electron diffraction (LEED) and reflection high-energy electron diffractio n (RHEED). We found that the crystal quality and the surface smoothness of the homoepitaxial diamond on (111) strongly depends on the substrate temper ature; the highest quality homoepitaxial diamond on (111) can be successful ly grown at 690 degrees C. The highest quality homoepitaxial diamond had th e smoothest C(111)-1 X 1 surface, which was evidenced by the first observat ion of sharp and clear Kikuchi patterns, comparable, to those of a C(001) s urface. Caution has to be exercised when judging the structure of a C(111) surface from a LEED(1 X 1) pattern, because its observation can encompass s urface morphologies ranging from single-crystal to polycrystalline diamonds . In contrast, surface roughness has a dramatic effect on the. RHEED diffra ction pattern. In the smoothest C(001)- 2 X 1/1 X 2 surface, the RHEED patt ern shows spots rather than streaks. Growth on a (110) diamond surface resu lts in {111}-oriented microfacets. (C) 1999 American Vacuum Society. [S0734 -2101(99)07805-7].