N. Matsuyama et al., Amorphous diamond-like carbon film prepared by pulsed laser deposition with application of pulsed negative bias voltage, J APPL PHYS, 89(3), 2001, pp. 1938-1941
Amorphous diamond-like carbon films were prepared by pulsed laser depositio
n with a synchronized application of pulsed negative bias voltage to the su
bstrate. A beam from a Nd:yttrium-aluminum-garnet laser (1064 nm) was radia
ted to a graphite target at a laser fluence of 10 J/cm(2). The negative bia
s voltage was changed from 0 to 10 kV at a repetition rate of 10 Hz. The fi
lm was deposited on a Si (111) substrate at a chamber pressure of 5 x 10(-5
) Torr for 120 min. The effects,of bias voltage on the structure of the fil
m were discussed on the basis of the measured deposition rate, Raman spectr
a, refractive index, dynamic hardness, and surface roughness. The effect of
self-sputtering on deposition rate was observed at a negative bias voltage
above 0.6 kV. The application of bias voltage increased the fraction of sp
(3) configuration in the film and made the film surface smoother. In partic
ular, the application of 3 kV gave the largest fraction of sp(3) bonding, a
nd formed the hardest and smoothest film. Bias voltage above 5 kV, however,
drastically reduced the hardness of the film. (C) 2001 American Institute
of Physics.