AVS 45th International Symposium
    Selected Energy Epitaxy Topical Conference Wednesday Sessions
       Session SE-WeM

Paper SE-WeM11
Velocity, Temperature, and Chemical Composition of a dc-Arcjet Plume

Wednesday, November 4, 1998, 11:40 am, Room 327

Session: Selected Energy Epitaxial Growth Processes
Presenter: J.B. Jeffries, SRI International
Authors: J.B. Jeffries, SRI International
J. Luque, SRI International
W. Juchmann, SRI International
Correspondent: Click to Email
Laser-induced fluorescence, optical emission, and Langmuir probe measurements are used to characterize the reactive plume of a dc-arcjet reactor during diamond deposition. We find one third of the feedstock hydrogen is dissociated into atoms. Optical measurements are used to determine spatially resolved gas temperature, plume velocity, and the spatial variation of the concentrations of reactive intermediates. The atomic hydrogen concentration is not in equilibrium with the gas temperature, and finite rate chemistry controls the concentrations of the reactive intermediate species in the plume. The supersonic directed velocity of the plume produces a shock structure just above the substrate. The temperature and pressure gradient produced by this shock influences the chemical composition of the gases in the boundary layer and the transport of reactants to the surface. Supported by ARO and DARPA via the NRL.