In situ characterization of Mn and Fe silicide islands on silicon Miyoko Tanaka * , Qi Zhang, Masaki Takeguchi, Kazuo Furuya Nanomaterials Laboratory, National Institute for Materials Science, 3-13, Sakura, Tsukuba 305-0003, Japan Abstract The Mn and Fe deposited clean Si(1 1 1) substrates were examined with UHV-TEM and STM that are part of an UHV-TEM/STM integrated characterization system. The Mn deposition with coverages of 5–20 ML followed by annealing at 673 K for 5 min formed MnSi islands. STM image revealed their surface p 3  p 3 structure. The re- deposition of 10–20 ML Mn and re-annealing at 573 K for 5 min succeeded to transform the MnSi islands into MnSi 1:7 . The Fe deposition with coverages of 5–20 ML followed by annealing at 873 K for 5 min formed b-FeSi 2 islands. TEM image of these islands showed Moire fringes in different directions. Ó 2003 Elsevier Science B.V. All rights reserved. Keywords: Electron microscopy; Scanning tunneling microscopy; Manganese; Iron; Silicides; Surface structure, morphology, roughness, and topography 1. Introduction Transition metal silicide-silicon systems have been investigated extensively for both technologi- cal and scientific use. Most silicides are metallic and thus are used for contacts, gates, etc. [1], but some silicides are semiconducting and are po- tential candidates for silicon-based optoelectronic devices or thermoelectric materials [2]. b-FeSi 2 is the most promising material with its light emitting character [3]. On the other hand, MnSi 1:7 is an- other candidate with its direct band gap around 0.7 eV and the possibility of epitaxial growth [4]. A number of studies have been made to investigate its growth mechanism, optical property, structure, and so on [5–8]. However, their structures and properties at the early stage of their growth have not been resolved well yet. Even epitaxial rela- tionship has not been determined uniquely. In the present work, we report the structures and properties of the small Mn and Fe silicide is- lands formed epitaxially on Si(1 1 1) observed by transmission electron microscopy (TEM) and scanning tunneling microscopy (STM) with UHV- TEM/STM combined system. Same samples are observed with both TEM and STM. Images of surface structures of the islands representing their bulk structures are obtained. Epitaxial relationship between the islands and the substrate Si are also discussed. 2. Experiment All experiments were done in an UHV-TEM/ STM integrated characterization system (UT- SICS). UTSICS is a multi-chamber, UHV surface characterization and preparation system that is attached to an UHV-FE-TEM and an UHV-STM. * Corresponding author. Tel.: +81-298-59-5053; fax: +81- 298-59-5054. E-mail address: tanaka.miyoko@nims.go.jp (M. Tanaka). 0039-6028/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0039-6028(03)00213-9 Surface Science 532–535 (2003) 946–951 www.elsevier.com/locate/susc