Possible behavior of a diamond (111) surface in methane/hydrogen systems
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (USA)
A combined numerical and experimental investigation into the behavior of diamond (111) surfaces in plasma CVD reactors is presented. Numerically, semiempirical molecular orbital methods are used as a model of diamond (111) surfaces represented by a 20-atom carbon cluster plus surface species. The abstraction of hydrogen atoms by gas-phase hydrogen atoms, the coverage dependence of the heat of formation for submonolayers of CH{sub 3} and C{sub 2}H groups coadsorbed with H, and the energy change for abstraction of H atoms from the surface by various radicals in the gas-phase are examined. No barrier to abstraction is found, steric effects in achieving clusters of CH{sub 3} groups are large, and C{sub 2}H and atomic oxygen are found to be the most energetically favored for removal of adsorbed H. Experimentally, relative concentrations of atomic H in the near-surface region as a function of added O{sub 2} mole fraction were measured. A weak dependence on O{sub 2} concentration is observed, but does not appear to be significant enough to account for observed changes in growth rate. This suggests that other radical species be investigated for their contribution to diamond film growth.
- OSTI ID:
- 6334313
- Journal Information:
- Journal of Materials Research; (USA), Journal Name: Journal of Materials Research; (USA) Vol. 5:11; ISSN JMREE; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
Similar Records
Diagnostics of filament-assisted diamond growth chemistry
Nonlinear optical spectroscopy of diamond surfaces
Related Subjects
360601* -- Other Materials-- Preparation & Manufacture
ADSORPTION
ALKANES
CARBON
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
DEPOSITION
DIAMONDS
ELEMENTAL MINERALS
ELEMENTS
ENTHALPY
FILMS
FORMATION HEAT
HYDROCARBONS
HYDROGEN
METHANE
MINERALS
MOLECULAR ORBITAL METHOD
NONMETALS
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
OXYGEN
OXYGEN ADDITIONS
PHYSICAL PROPERTIES
PLASMA
QUANTITY RATIO
REACTION HEAT
REACTORS
SORPTION
SURFACE COATING
SURFACE PROPERTIES
THERMODYNAMIC PROPERTIES
THIN FILMS