Carbon nitride films were deposited at 20, 250 and 500 degrees C on [1
11] Si substrates by XeCl laser ablation of graphite in low pressure (
1-50 Pa) N-2 atmosphere at fluences of 12 and 16 J/cm(2). Different di
agnostic techniques (SEM, TEM, RBS, XPS, XRD) were used to characteriz
e the deposited films. Films resulted plane and well adhesive to their
substrates. N/C atomic ratios up to 0.7 were inferred from RBS measur
ements in films deposited at 20 degrees C and 16 J/cm(2). Nitrogen con
centration increases with increasing ambient pressure and laser fluenc
e. The N 1s peak of the XPS spectra indicate two different bonding sta
tes of nitrogen atoms to C atoms, while the C 1s peak, apart from the
two bonding states to nitrogen atoms, indicates one bonding state with
regard to carbon atoms. XRD and TEM analyses point to an oriented mic
rocrystalline structure of the films. Heating of the substrate results
in a lower nitrogen concentration in respect of films deposited at 20
degrees C in otherwise identical experimental conditions. Optical emi
ssion studies of the laser plasma plume indicate a correlation between
the emission intensity of the CN radicals in the plume and the nitrog
en atom concentration in the films. (C) 1998 Elsevier Science B.V.