TITLE

Microstructure and phase composition evolution of nano-crystalline carbon films: Dependence on deposition temperature

AUTHOR(S)
Hoffman, A.; Heiman, A.; Strunk, H. P.; Christiansen, S. H.
PUB. DATE
March 2002
SOURCE
Journal of Applied Physics;3/1/2002, Vol. 91 Issue 5, p3336
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Nano-crystalline carbon films possessing a prevailing diamond or a graphite character, depending solely on substrate temperature and deposition time, can be deposited from a methane-hydrogen mixture by the direct current glow discharge plasma chemical vapor deposition method. In this study we investigate the evolution of nano-crystalline carbon films deposited in the 800-950°C temperature range onto silicon substrates aiming to enlight the physicochemical processes leading to the formation of nano-diamond films. While at a deposition temperature of ∼880 °C the formation of a thin precursor graphitic film is followed by deposition of a film of diamond character, at higher and lower temperatures the films maintain their graphitic character. The morphology of the films and their growth rate vary with deposition temperature: slower growth rates and higher film roughness are obtained at lower temperatures suggesting the importance of kinetic effects during the growth process. For deposition times longer than ∼60 min, similar morphologies are obtained irrespectively of the deposition temperature. A preferred spatial alignment of the basal planes of the graphitic film at the interface with the silicon substrate was determined. The alignment was found to differ with deposition temperature: at 800 and 880°C the alignment occurs along the graphitic a axis perpendicular to the silicon substrate, while at 950 °C the c axis is aligned perpendicular to the silicon substrate. However, it was determined that for films a few hundred nm thick close to the evolving surface the films display a preferred alignment of the basal planes vertical to the surface, irrespectively of their orientation at the interface. The reason for this alignment is suggested to be associated with a stress relaxation mechanism in the graphitic films. It was determined that film growth is accompanied by the evolution of large local stresses which obtain a maximum value for the...
ACCESSION #
6221056

 

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics