We describe a novel carbon hollow-cathode RF plasma reactor which has been used to prepare deposits of carbon nitride. Results of the characterization of the deposits by Fourier transform infrared (FTIR) microscopy, Raman microscopy, transmission electron microscopy (TEM), energy-dispersive X-ray analysis and X-ray diffraction are presented. The variation of the properties of the deposits as a function of the deposition conditions is discussed. The inclusion of small quantities of methane in the gas mixture was found to enhance the formation of the CN deposit, but for conditions of maximum enhancement C-H and N-H groups were observed in the deposit. Elemental analysis of the deposit showed that the nitrogen content was similar to 57 at.%. A crystalline deposit was obtainable at low substrate temperatures, and the crystals were seen to grow preferentially on defects on the substrate surface. (C) 1998 Elsevier Science S.A. All rights reserved.