We have reported a one step growth of a high quality beta-FeSi2 epitaxial film on hydrogen terminated Si(1 1 1) by using molecular beam epitaxy (MBE) without template layer or post-growth annealing. In the present work, the growth process was studied by analyzing X-ray diffraction (XRD) spectra, reflective high energy electron diffraction (RHEED) and atomic force microscopy (AFM) observations on the samples grown with different growth times from 10 s to 1 h. A phase transformation from gamma-FeSi2 to beta-FeSi2 was confirmed existing in the crystal film growth, as well as the growth mode changing from three-dimensional (3D) to two-dimensional (2D) mode. (c) 2006 Elsevier B.V. All rights reserved.