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Title: Infrared spectroscopic and modeling studies of H{sub 2}/CH{sub 4} microwave plasma gas phase from low to high pressure and power

InfraRed Tunable Diode Laser Absorption Spectroscopy technique has been implemented in a H{sub 2}/CH{sub 4} Micro-Wave (MW frequency f = 2.45 GHz) plasma reactor dedicated to diamond deposition under high pressure and high power conditions. Parametric studies such as a function of MW power, pressure, and admixtures of methane have been carried out on a wide range of experimental conditions: the pressure up to 270 mbar and the MW power up to 4 kW. These conditions allow high purity Chemical Vapor Deposition diamond deposition at high growth rates. Line integrated absorption measurements have been performed in order to monitor hydrocarbon species, i.e., CH{sub 3}, CH{sub 4}, C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 6}. The densities of the stable detected species were found to vary in the range of 10{sup 12}–10{sup 17} molecules cm{sup −3}, while the methyl radical CH{sub 3} (precursor of diamond growth under these conditions) measured into the plasma bulk was found up to 10{sup 14} molecules cm{sup −3}. The experimental densities have been compared to those provided by 1D-radial thermochemical model for low power and low pressure conditions (up to 100 mbar/2 kW). These densities have been axially integrated. Experimental measurements under high pressure and power conditions confirmmore » a strong increase of the degree of dissociation of the precursor, CH{sub 4}, associated to an increase of the C{sub 2}H{sub 2} density, the most abundant reaction product in the plasma.« less
Authors:
; ;  [1] ; ;  [2] ;  [3]
  1. LSPM CNRS UPR 3407 Université Paris 13, 99 Avenue J.-B. Clément, 93430 Villetaneuse (France)
  2. INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)
  3. GREMI UMR 7344, CNRS/Université d'Orléans, site de Bourges, rue G. Berger, 18000 Bourges (France)
Publication Date:
OSTI Identifier:
22314368
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; ABSORPTION SPECTROSCOPY; CHEMICAL VAPOR DEPOSITION; DIAMONDS; DISSOCIATION; ETHANE; ETHYLENE; GHZ RANGE; HYDROGEN; IMPURITIES; LASERS; METHANE; METHYL RADICALS; MICROWAVE RADIATION; PARAMETRIC ANALYSIS; PLASMA; PRESSURE RANGE MEGA PA 10-100; SIMULATION