The surface morphology of C:N films deposited by a pulsed cathodic arc discharge (PCAD) method at nitrogen pressure in the range of 0.2-15 Pa was studied by atomic force microscopy (AFM). The roughness parameter Ra was found to be changed from 0.25-0.30 nm for nitrogen-free film to 1.55-1.60 nm for C:N film with 40 at.% of the nitrogen content at PN2 = 1-2 Pa. The further increase of PN2 up to 15 Pa results in locally non-uniform surface morphology. It is assigned to the formation of a polymeric phase in the film. The correlation of the surface morphology and chemical bonding in PCAD C:N films is discussed. © 1998 Elsevier Science B.V. All rights reserved.