Infrared detection of gaseous species during the filament-assisted growth of diamond

Abstract

Infrared diode laser absorption spectroscopy is employed as an in situ method to examine gas phase species present during filament-assisted deposition of diamond films. From a reactant mixture of 0.5% methane in hydrogen, methyl radical (CH3 ), acetylene (C2H2), and ethylene (C2H4 ) are detected above the growing surface, while ethane (C2H6 ), various C3 hydrocarbons, and methylene (CH2) radicals are below our sensitivity levels. The growth of polycrystalline diamond films on Si wafers and polycrystalline Ni is confirmed with x-ray and Raman scattering, scanning electron microscopy, and Auger electron spectroscopy.