We studied the growing process of Ge dots on silicon substrates covered with an ultrathin silicon dioxide buffer layer which was formed with simple chemical procedure. Uniform and densely packed (10(11) cm(-2)) quantum dots (QDs) were obtained by optimizing the growth parameter with the MBE method. The influence of temperature, coverage, as well as the post-annealing process, on the epitaxial and non-epitaxial nanodots formation was evaluated. Nano-sized high density quantum dots were also realized with different growing conditions, whose structural and growing mechanism were discussed under the help of SEM and RHEED results. (C) 2009 Elsevier B. V. All rights reserved.