Co-sputtered copper-indium (Cu-In) alloy layers were investigated as precursors for CuInSe(2) (CIS) formation. Results of scanning electron microscopy (SEM), EDS and X-ray diffraction (XRD) studies reveal the inhomogeneity of the films composition. The films have a rough surface structure with well-defined islands crystallized within the film matrix. The elemental composition of the island-type crystals corresponds to the compound CuIn(2) and the composition of the matrix area corresponds to the CulIIn(9) phase. The influence of heating temperature, time and Se pressure on the morphology and composition of films is studied using SEM, XRD and Roman spectroscopies. Thereby optimal technological parameters for the production of single-phase CIS layers are determined. (C) 2008 Elsevier B.V. All rights reserved.