Scanning tunneling microscopy investigation at hightemperaturesofislandsandholesonSi111)7  7inreal time: evidence for diusion-limited decay S. Hildebrandt a , A. Kraus b , R. Kulla b , G. Wilhelmi c , M. Hanb ucken d , H. Neddermeyer b,d, * a Physica Status Solidi, Wiley±VCH Verlag Berlin GmbH, B uhringstrasse 10, D-130086 Berlin, Germany b Fachbereich Physik, Martin-Luther-Universit at Halle±Wittenberg, D-06099 Halle, Germany c Institut f ur Experimentalphysik, Ruhr-Universit at Bochum, D-44780 Bochum, Germany d CRMC2-CNRS, Campus Luminy, Case 913, F-13288 Marseille, France Received 27 September 2000; accepted for publication 27 March 2001 Abstract The annealing behavior of hole- and island-like nanostructures fabricated in situ in the scanning tunneling micro- scopeonSi111)7  7hasbeeninvestigatedintherangefrom720to830K.Incontrasttopreviouswork,theanalysis revealsdiusion-controlleddecaykineticstobedescribedbya t 0  t 2=3 law.Fromthetemperaturedependenceofthe diusioncoecient,weobtainanactivationenergyof1:49  0:12)eVwhichisdiscussedintermsofadiusionbarrier for the moving adatoms. The comparison of the decay between hole and island structures suggest a missing Ehrlich± Schwoebel barrier for hole ®lling. Ó 2001 Elsevier Science B.V. All rights reserved. Keywords: Silicon; Scanning tunneling microscopy; Surface diusion; Surface structure, morphology, roughness, and topography 1. Introduction Thecreationofislandsandholesonthesurface ofSi111)7  7bythetipofascanningtunneling microscopeSTM)hasattractedalargenumberof research groups [1±7]. The interest is not only based on the possibility to pattern surfaces in the nm range but also on the unique capability of STMtostudystructureandstabilityofsmallnon- equilibrium features on an atomic level. The fun- damental processes derived in this way are also important for understanding of the structural be- havior of larger structures in the micrometer or millimeter range which may be created by litho- graphic or other etching techniques [8] and which may become important in technical devices. It has to be mentioned that a large amount of work has already been done in related ®elds of the present work.Herewehavetoconsidertheeortsofother groups to characterize steps and their interaction, the structure of vicinal surfaces of Si, growth studiesofSiandtheoreticalworkonstructureand growth. Relevant publications will be cited later. Surface Science 486 2001) 24±32 www.elsevier.nl/locate/susc * Corresponding author. Address: Fachbereich Physik, Mar- tin-Luther-Universit at Halle±Wittenberg, D-06099 Halle, Ger- many. Tel.: +49-345-55560; fax: +49-345-5527160. E-mail address: neddermeyer@physik.uni-halle.de H. Neddermeyer). 0039-6028/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII:S0039-602801)01054-8