Tg. Owano et Ch. Kruger, PARAMETRIC STUDY OF ATMOSPHERIC-PRESSURE DIAMOND SYNTHESIS WITH AN INDUCTIVELY-COUPLED PLASMA TORCH, Plasma chemistry and plasma processing, 13(3), 1993, pp. 433-446
Polycrystalline diamond coatings have been deposited on molybdenum and
silicon substrates using an inductively coupled, atmospheric-pressure
plasma torch. Growth rates are on the order of 10 mum/hr. The inducti
vely coupled plasma reactor is found to produce a uniform, well-charac
terized growth environment for experimental and computational study of
the atmospheric-pressure diamond growth regime. Growth morphology is
found to be sensitive to reactor conditions such as substrate surface
temperature and methane-to-hydrogen feed ratio. An experimental parame
tric study of these variables is performed and the resultant growth an
alyzed by scanning electron microscopy, Raman spectroscopy, and X-ray
diffraction. Spectroscopic analysis of the gas phase is also performed
Results indicate that the substrate temperature range over which diam
ond growth occurs shifts toward higher temperatures as the methane-to-
hydrogen feed ratio is increased The growth rate is observed to reach
a maximum with varying methane-to-hydrogen feed ratio at constant subs
trate temperature. Raman analysis of the deposits indicates that highe
r-quality diamond is achieved at the highest limits of substrate tempe
rature for a given methane-to-hydrogen ratio. Higher-quality diamond i
s also observed to be formed al lower methane-to-hydrogen feed ratios.