ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Valence-band as well as Si(2p) and C(1s) core-level photoemission, Auger, and near-edge x-ray-absorption fine-structure spectroscopies were used to follow the surface chemistry associated with diamond film deposition with a filament-assisted chemical-vapor-deposition reactor on atomically clean and diamond polished Si(100) and Si(111) surfaces. Raman spectroscopy and atomic force microscopy (AFM) were also used ex situ to characterize the deposited films. Within 3 min of deposition, a carbon-rich SiC layer, at least 13 A(ring) thick, was observed to develop. At early stages of growth (〈10 min of deposition), no differences were observed between the clean and diamond-polished surfaces. With additional deposition, a 20–30-A(ring)-thick amorphous carbon overlayer was deposited on the clean Si surfaces: The amorphous carbon layer did not promote diamond nucleation. Deposition of an a-C:H layer on top of the amorphous carbon layer also did not promote diamond nucleation. In contrast, ∼500 A(ring) diamond films were deposited within 45–60 min on the diamond-polished surfaces. Two types of nuclei were observed following 20 min of deposition by atomic force microscopy: (1) large (200–300 nm in diameter) nuclei, randomly distributed on the surface; and (2) smaller (50–100 nm) nuclei that show a preference for forming along the scratches. Atomic force micrographs of the originally clean surface show the formation of sharp relief structures on the surface. These structures, combined with the amorphous carbon overlayer, may be responsible for the few sites that do nucleate diamond on unpolished Si surfaces.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.357166
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