Journal of Crystal Growth 237–239 (2002) 2035–2040 Self-organized growth of nanosized flat dots and vertical magnetic Co pillars on Au(111) O. Fruchart a,b, *, G. Renaud c , J.-P. Deville d , A. Barbier c , F. Scheurer d , M. Klaua b , J. Barthel b , M. Noblet c , O. Ulrich c , J. Man ! e-Man ! e d , J. Kirschner b a Laboratoire Louis N ! eel, CNRS, BP166, F-38042, Grenoble Cedex 9, France b MPI f . ur Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany c DRFMC/SP2M/IRS (CEA), 17 Rue des Martyrs, F-38054 Grenoble Cedex 9, France d IPCMS (UMR 7504 CNRS-ULP), 23 rue du Loess, F-67037 Strasbourg Cedex, France Abstract We report various experiments that cast some light on the growth process of self-organized dots and vertical Co pillars on Au(11 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. r 2002 Elsevier Science B.V. All rights reserved. PACS: 68.65.+g; 68.35.Bs; 61.16.Ch; 61.10.Eq Keywords: A1. Grazing incidence small angle X-ray diffusion; A1. Low dimensional structures; A1. Nanostructures; A1. Surface processes; A3. Molecular beam epitaxy; B2. Magnetic materials 1. Introduction Self-organized (SO) epitaxial growth has re- ceived much attention for its ability to produce spontaneously high quality nanostructures down to the low nanometer range. Whereas epitaxial SO was first demonstrated to yield rather flat struc- tures in the first stages of growth, a new search path consists in growing three-dimensional (3D) self-organized structures by sequential deposition [1,2]. Among the motivations are pushing the limits of SO versatility, as well as potential applications that usually require larger amounts of active material than simply fractions of atomic layers. Whereas 3D SO usually consists of dot stack- ings, it was shown recently that continuous vertical structures may be grown as well. This way, laterally ordered arrays of vertical magnetic Co pillars with a density of more than 10 12 cm 2 [2] were fabricated. The purpose of this article is to report experiments casting some light on effects relevant to vertical growth. We first report grazing incidence small angle X-ray scattering (GISAXS) experiments performed on mono-atomic deposits, *Corresponding author. Laboratoire Louis N! eel, CNRS, BP166, F-38042, Grenoble Cedex 9, France. Tel.: +33476- 887920; fax: +33476-881191. E-mail address: fruch@polycnrs-gre.fr (O. Fruchart). 0022-0248/02/$-see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0022-0248(01)02305-3