Jk. Lee et al., EFFECT OF ADDITIONAL GAS ON DIAMOND DEPOSITION BY DC PACVD, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 209(1-2), 1996, pp. 399-404
The effect of the addition of Ar and nitrogen gas on the deposition of
diamond using a direct current (DC) plasma of CH4-H-2 gas mixture is
investigated. The DC plasma is generated by applying a voltage between
820 and 900 V and the resulting current is between 5.5 and 6 A. The a
ddition of Ar makes the plasma unstable and is limited to 5% owing to
the plasma extinction at higher Ar concentrations. Growth rate and non
-diamond carbon content in the diamond film increase with the Ar amoun
t slightly irrespective of deposition temperature. An optical emission
spectrum shows the increase of emission of C-2 and CH while showing a
constant average electron energy of the plasma. On the contrary, by a
dding nitrogen, the morphology is changed to a ball-like diamond shape
as well as growth rate of diamond film is decreased abruptly. The opt
ical emission intensities of C-2 and hydrogen also show an abrupt drop
with the nitrogen addition. The role of plasma species in the deposit
ion behaviour of diamond is also discussed.