Copper nitride (Cu3N) thin films were prepared on glass substrates by reactive radio-frequency (RF) magnetron sputtering tinder different nitrogen flow rate. The thermal stability of the Cu3N films was investigated through vacuum annealing treatment at different temperature. X-ray diffraction, scanning electron microscopy and near-normal reflectance spectra were employed to characterize the films. The deposited Cu3N films take on a different preferred orientation, which changed from (1 1 1) to (1 0 0) with increase of N-2 ratio. The grains size of thin films can become small when the N-2 ratio increases. The Cu3N phase can completely decompose into Cu and N-2 through vacuum annealing treatment at a temperature of 200degreesC. The reflectance of as-deposited Cu3N films is quite different from decomposed films. (C) 2004 Elsevier B.V. All rights reserved.