Carbon nitride films deposited onto room temperature silicon substrates by ArF excimer laser ablation of a graphite target in nitrogen atmosphere have been investigated after floating off in transmission electron microscope (TEM). All films fabricated in the 1 - 100 Pa N-2 pressure and 1 - 10 J cm(-2) fluence domain are amorphous. It is the nitrogen pressure that governs both the composition and the morphology of the films. the effect of the laser fluence being weaker. The morphologies range from dense films grown in 1-5 Pa N-2, to structures composed of carbon nitride clusters and voids between them, obtained at and above 50 Pa N-2. Ablation with pulses of high fluence (10 J cm-2) results in more compact films, The oxygen content determined by energy dispersive X-ray spectrometry well correlates with the compactness of the films, being significantly higher in those fabricated at higher pressures and composed of clusters. (C) 2002 Elsevier Science B.V.. All rights reserved.