T. Ujvari et al., Composition and chemical structure characteristics of CNx layers prepared by different plasma assisted techniques, SOL ST ION, 141, 2001, pp. 63-69
CNx layers were grown on Si (100) wafers and cleaved NaCl (100) slices by r
eactive sputtering of graphite in DC nitrogen plasma, by DC and RF magnetro
n sputtering of graphite in N-2 or N-2 + Ar mixture, and from C-containing
precursors in nitrogen by plasma-enhanced chemical vapour deposition (PECVD
). The chemical structure of the deposited layers was characterised by XPS
and FT-IR spectroscopy. DC plasma deposition resulted in layers with high N
content, close to CN stoichiometry(x approximate to 1), as determined by X
PS. The CNx layers deposited by DC or RF magnetron sputtering contained 22-
32 at.% N (x = 0.3-0.5). For layers prepared by PECVD, N-content varying be
tween 20 and 50 at.% was characteristic. The broad and asymmetric C1s and N
1s XPS spectral lines manifested several chemical bonding states of the con
stituents. The proportions of the line components varied with the preparati
on conditions. Significant differences were also observed in the 1100-1700
cm(-1) region of the FT-IR spectra. Assignment of the two major N1s photoel
ectron peak-components was proposed based on the established correlation be
tween the FT-LR results, composition and binding energy values measured for
magnetron-deposited CNx phases as follows: the N1 at 398.3 eV BE to N=C do
uble bonds and N2 at 400.2 eV BE to N-C single bonds. (C) 2001 Elsevier Sci
ence B.V. All rights reserved.