Characterization of bias-enhanced nucleation of diamond on silicon by invacuo surface analysis and transmission electron microscopy
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States)
An in-depth study has been performed of the nucleation of diamond on silicon by bias-enhanced microwave plasma chemical vapor deposition. Substrates were pretreated by negative biasing in a 2% methane-hydrogen plasma. The bias pretreatment enhanced the nucleation density on unscratched silicon wafers up to 10{sup 11} cm{sup {minus}2} as compared with 10{sup 7} cm{sup {minus}2} on scratched wafers. {ital In} {ital vacuo} surface analysis including x-ray photoelecton spectroscopy (XPS), Auger electron spectroscopy, and combined XPS and electron-energy-loss spectroscopy were used to study systematically both the initial-nucleation and growth processes. High-resolution cross-sectional transmission electron microscopy (TEM) was used to study the physical and structural characteristics of the diamond-silicon interface as well as to complement and enhance the {ital in} {ital vacuo} surface-analytical results. Raman spectroscopy confirmed that diamond was actually nucleating during the bias pretreatment. Scanning electron microscopy has shown that once the bias is turned off, and conventional growth is conducted, diamond grows on the existing nuclei and no continued nucleation occurs. If the bias is left on throughout the entire deposition, the resulting film will be of much poorer quality than if the bias had been turned off and conventional growth allowed to begin. Intermittent surface analysis showed that a complete silicon carbide layer developed before diamond could be detected. High-resolution cross-sectional TEM confirmed that the interfacial layer was amorphous and varied in thickness from 10 to 100 A. A small amount of amorphous carbon is detected on the surface of the silicon carbide and it is believed to play a major role in the nucleation sequence.
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 7201389
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 45:19; ISSN PRBMD; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360606* -- Other Materials-- Physical Properties-- (1992-)
CARBON
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
DEPOSITION
DIAMONDS
ELECTRON MICROSCOPY
ELEMENTAL MINERALS
ELEMENTS
INTERFACES
LASER SPECTROSCOPY
MICROSCOPY
MINERALS
NONMETALS
NUCLEATION
RAMAN SPECTROSCOPY
SEMIMETALS
SILICON
SPECTROSCOPY
SURFACE COATING
TRANSMISSION ELECTRON MICROSCOPY