The influence of the electrochemical potential and the deposition mode on the preferred orientation and morphology of crystallites and on the microstrain in electrochemically deposited copper thin films was investigated using a combination of cyclic voltammetry, chronoamperometry, X-ray diffraction, SEM and the diffraction of backscattered electrons. With increasing negative electrochemical potential, the deposition mode changed from the charge transfer controlled one to the diffusion controlled one. At the highest electrochemical potentials, copper deposition was accompanied by hydrogen reduction. In potentiostatically deposited thin films, the preferred orientation of crystallites changed from {111} in the charge transfer controlled deposition mode to {110} in the diffusion controlled one. The increase of the electrochemical potential in the charge transport controlled deposition mode caused an increase of the dislocation density. The increasing electrochemical potential in the diffusion controlled mode led to a decrease of the dislocation density. The copper deposition, which was accompanied by the hydrogen reduction, produced needle-like crystallites with the {100} texture and with the lowest dislocation density. (C) 2007 Elsevier B.V. All rights reserved.