Observation of surface modification and nucleation during deposition of diamond on silicon by scanning tunneling microscopy

The surface topography of silicon substrates after the initial stages of diamond growth, by microwave plasma enhanced chemical vapor deposition, has been observed by scanning tunneling microscopy. The initial surfaces were polished with diamond paste before deposition to enhance nucleation, and the scratches were examined. After one half hour growth, the surface showed additional topography over all regions, and widely spaced faceted structures were detected which were attributed to diamond nuclei. The surface between nuclei showed increased roughness with increased deposition time. The faceted nuclei were found along the scratches. The nuclei showed facets which were smooth to within 5 Å. Fingerlike ridge structures were found extending from and in-between some of the nuclei. These structures indicate a mechanism of the lateral diamond growth. The electronic properties of the surface were probed by local I-V measurements, and characteristics attributable to SiC were observed.