The growth mechanism of the elongated NiSi2 Clusters was investigated according to the shape distribution observed and the strain energy calculated in this experiment. Because the shape distribution of the NiSi2 clusters observed here cannot be explained by the energetic model, we infer that the elongation process of the NiSi2 Clusters should be mainly governed by the growth kinetics. An existing kinetic model, which has been used to explain the elongation process of a single epitaxial structure, is expanded to explain the trend of the shape distribution observed in this experiment. (C) 2007 Elsevier B.V. All rights reserved.