[en] Deposition of carbon nitride films on Si(001) substrates was carried out in a dual dc magnetron sputtering system. High-purity (99.99%) pyrolytic graphite and Si targets of 7.5 cm diameter were sputtered in 1.8-3 mTorr N₂. The targets were positioned 10 cm from a resistively-heated substrate holder. The base pressure of the deposition chamber was ∼5x10^-7 Torr. Films were grown at a substrate temperature of 20-700 grad C at floating potential. A series of films with thickness ∼1 mm were grown on all the substrates at a constant magnetron current of 0.2 A, which resulted in a deposition rate of 0.1-0.3 nm/s. Structural characterisations were performed by high-resolution transmission electron microscopy (HRTEM) using a Philips CM 20 electron microscope operated at 200 kV (resolution ∼0.28 nm) equipped with a Ge detector Noran EDS system. Plan-view and cross-sectional HRTEM samples were obtained by low angle (<4 grad) Ar⁺ ion-beam milling at 10 keV energy, which was decreased to 3 kV in the end of the procedure. The appearance of the above structures depended on film composition. The turbostratic structures are characteristic for large C and N concentrations, near to the C corner of the compositional triangle. Columnar structures appear as a consequence of the increasing Si content. In the middle of the triangle the structures are rather homogeneous. Apparently, the substrate temperature does not make a strong influence on the above described structures, as long as it does not rise above 700 grad C. (Authors)