Lr. Shaginyan et al., Influence of different physical factors on microstructure and properties of magnetron sputtered amorphous carbon films, THIN SOL FI, 397(1-2), 2001, pp. 288-295
Structure evolution of amorphous carbon (a-C) films deposited by dc magnetr
on sputtering of graphite in argon was investigated as a function of substr
ate temperature T-s (20-800 degreesC) and dc substrate bias voltage U-b (fl
oating - - 175 V). Film structure was studied by transmission electron micr
oscopy, selected area electron diffraction, reflective high energy electron
diffraction and Raman spectroscopy. Film resistivity in two directions - p
arallel and perpendicular to the substrate - was also measured. The results
obtained allow for the assumption that the film structure is based on coex
istence of D- and G-phases formed of sp(2) bonded carbon atoms. G-phase con
sists of small graphite-like ordered areas embedded in continuous uniform a
morphous D-phase. The evolution of a-C film structure in 20-450 degreesC in
terval occurs by temperature induced graphite-like ordering of small areas
within D-phase (G-phase nucleation). In the 500-800 degreesC range the chan
ge of C-film growth mechanism takes place, Instead of nucleation of the G-p
hase within the D-phase the initial nuclei of graphite phase appears on the
substrate. The changes of a-C film microstructure under the ion bombardmen
t in the range of -20 less than or equal toU(b)less than or equal to -150 V
are accompanied by decreasing of G-phase clusters size and simultaneous ce
rtain disordering in their internal structure. At U-p > - 150 V the cluster
structure tends to be more ordered towards it graphitization. The effect o
f graphite-like clusters 'texturing' revealed in a-C films under the ion bo
mbardment is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.