P. Patsalas et al., A complementary study of bonding and electronic structure of amorphous carbon films by electron spectroscopy and optical techniques, DIAM RELAT, 10(3-7), 2001, pp. 960-964
A complementary study of composition and bonding of sputtered a-C films, de
posited on Si(001) substrates with various bias voltages (V-b) applied to t
he substrate during deposition is presented. The sp(3) and sp(3) fractions
in the films were calculated by deconvolution of the X-ray photoelectron sp
ectroscopy (XPS) Cls peak and studied by the differential auger electron sp
ectroscopy (AES) C1s peak signal. The results of this analysis are compared
with the estimation of sp(3) fraction calculated by spectroscopic ellipsom
etry (SE) and validated using density measurements by X-ray reflectivity. I
t was observed a considerable increase of sp(3) content in films deposited
with negative V-b. The respective sp(3) and sp(2) fractions and Ar concentr
ation with respect to the V-b and the depth profile analysis give valuable
information on the deposition mechanism of the sputtered a-C films. XPS val
ence band spectra provided the electron density of states in the a-C films'
valence band. The characteristic broad p band of diamond was prominent in
most of the films. The valence band structure of the films was correlated w
ith their optical response measured by SE. (C) 2001 Elsevier Science B.V. A
ll rights reserved.