The characteristics of nitrogen-doped Ge2Sb2Te5 thin films deposited on Si(100) substrates were investigated by X-ray diffraction (XRD) analysis, four-point probe and atomic force microscopy (AFM). It was found that the sheet resistance of the films annealed at 260 and 300 degreesC increased and the face-centered cubic (fcc) peaks of crystalline state of the films gradually disappeared with the increase of N-2 gas flow rate. At the N-2 gas flow rate of 12 seem, however, the sheet resistance of the film remarkably dropped to around that of crystalline state of undoped film and the crystal structure transformed from fcc to hexagonal. The RMS roughness values of the films decreased by the nitrogen doping. However, the surface of the film deposited at the N-2 gas flow rate of 12 seem was very rough due to crystallization of the film into hexagonal when the film was annealed at 260 degreesC for 20 min. (C) 2004 Elsevier B.V. All rights reserved.