Copper nitride (Cu3N) thin films were deposited on glass substrates by reactive radio-frequency magnetron sputtering of a pure copper target in a nitrogen/argon atmosphere. The deposition rate of the films gradually decreased with increasing nitrogen flow rate. The color of the deposited films was a reddish dark brown. The Cu3N films obtained by this method were strongly textured with crystal direction . The grain size of the polycrystalline films ranged from 16 to 26 nm. The Hall effect of the copper nitride (Cu3N) thin films was investigated. The optical energy gap of the films was obtained from the Hall coefficient and found to vary with the nitrogen content. The surface morphology was studied by scanning electron microscopy and atomic force microscopy. The copper nitride thin films are unstable and decompose into nitrogen and copper upon heat treatment when annealed in vacuum with argon protected at 200 °C for 1 h.