Journal of Crystal Growth 237–239 (2002) 21–27 Metal adsorption induced faceting on a Si(hhm) surface where m/h=1.4–1.5 Hiroki Minoda* Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro-ku, Tokyo 152-8551, Japan Abstract Initial stage of growth of Au on a Si(hhm) surface where m/h=1.4–1.5 (a Si(111) vicinal surface inclined by about 10.51 toward the ½ % 1 % 12 direction) was studied by high temperature STM. The Si(hhm) clean surface is destabilized by a small amount of Au adsorption and transforms into a stepped-(557) surface. The surface morphology changes by Au adsorption due to change of the surface energy and stabilized facet depend on Au coverage. The (557) surface transformed into a hill-and-valley structure composed of (335) and (111) facets, and it subsequently transformed into another hill-and-valley structure composed of (5511) and (111) facets. r 2002 Elsevier Science B.V. All rights reserved. PACS: 61.16.Ch; 61.82.Fk; 68.35.Bs Keywords: A1. Adsorption; A1. Crystal morphology; A1. Low dimensional structures; B2. Semiconducting silicon 1. Introduction Studies of crystal growth on semiconductor substrate are one of the important issues in the semiconductor industry. Nano-scale control of surface morphology of substrate and overgrown film is important and especially to prepare low dimensional small structures such as nano-dots and nano-wire is very important in the present industry. As a method to control surface morphol- ogy surfactant-mediated epitaxy was proposed about 10 years ago [1]. In this method a foreign material is pre-adsorbed on the substrate surface to modify properties of the substrate surface such as surface diffusion of overgrowth and the surface energy [1–5]. It is well known that most of the metals grow in Stranski–Krastanov mode on a low-index Si sur- face. In this growth mode the free energy of a low index surface of Si should be reduced by adsorp- tion of a foreign metal at the initial stage of the growth. Thus, we can expect that an original high index surface transforms into the hill-and-valley structure composed of two metal adsorbed low index Si surfaces by foreign metal adsorption at high temperature where attachment and detach- ment of Si atoms at steps take place. In this way, foreign metal adsorption on a substrate surface can modify surface morphology of the substrate as well as activation barrier of surface diffusion of overgrowth. This should give us a good template for nano-wires and nano-dots. We have been extensively studying Au-adsorp- tion-induced step bunching and faceting on Si surfaces including high index surfaces by using reflection electron microscopy and diffraction *Tel.: +81-3-5734-2481; fax: +81-3-5734-2079. E-mail address: hminoda@surface.phys.titech.ac.jp (H. Minoda). 0022-0248/02/$-see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0022-0248(01)01843-7