We report various experiments that cast some light on the growth process of self-organized dots and vertical Co pillars on Au(1 1 1). We first report grazing incidence small angle X-ray scattering (GISAXS) on Co dots and films, that allowed us to perform a crystallographic study of the order in the self-organized array, and also yielded a statistical view of the coalescence process. We then report scanning tunneling microscopy (STM) and spectroscopy (STS) images performed during the course of vertical growth. Details about the atomic growth process and the possible influence of the growth technique used are reported. (C) 2002 Elsevier Science B.V. All rights reserved.