CxByNz layers have been prepared by laser-assisted chemical vapour deposition (CVD) in a gas atmosphere containing C2H4, B2H6 and NH3 where the starting composition ratio could vary in a large range. The characterization of these C-B-N materials was made by XRD, EPMA, XPS, optical and scanning electron microscopy. The chemical composition of C-B-N layers tended to a composition C1B6N3 on the line BN-'B3C'. The turbostratic structure of C-B-N layers could be influenced and modified as a function of composition. XPS investigations confirmed the single-phase nature and the existence of bonding between all the elements. Some planar structures, containing especially CB2N groups, were suggested for the 'unit cell' of these C-B-N solid solutions, in agreement with EPMA and XPS analysis.