Surface Science 411 (1998) 54–60 Surface reconstruction suggests a nucleation mechanism in bulk: Sb/Si(113) and {113} planar defects J. Da ¸ browski *, H.-J. Mu ¨ssig, G. Wolff, S. Hinrich Institute for Semiconductor Physics, Walter-Korsing-Strasse 2, D-15230 Frankfurt (Oder), Germany Accepted for publication 18 April 1998 Abstract We report results of scanning tunneling microscopy measurements and ab initio total energy calculations showing that certain submonolayer coverages of Sb on Si(113), which is a stable surface resembling a mixture of Si(001) and Si(111), force some atoms into interstitial sites. The geometry is novel for surface reconstruction but closely related to the structure of bulk rodlike defects. This qualitatively new behavior of group V atoms on silicon shows that studies of passivated surfaces can provide data useful for verification of bulk defect models. © 1998 Elsevier Science B.V. All rights reserved. Keywords: Ab initio quantum mechanical methods and calculations; Antimony; Chemisorption; Density functional calculations; Low index single crystal surface; Scanning tunneling microscopy; Silicon; Surface relaxation and reconstruction Interactions between silicon surfaces and atoms easily dissolve in the bulk. Staying outside, they can attach to broken bonds of the surface atoms. of As or Sb control such processes as epitaxy of III–V films [1] on silicon, formation of delta- Yet broken bonds drive reconstruction of surfaces: the exposed atoms tend to move around and doping layers [2], and surfactant-mediated growth of SiGe films [3,4]. In all instances, these atoms rebond. With their bonds saturated, the surface atoms may relax to nearly bulk sites. Alternatively, are deposited onto a silicon surface. The consensus is that As and Sb atoms either replace surface Si the adsorbates may replace silicon at the surface. This transforms the broken bonds to fully occu- atoms, or build a separate overlayer [5–12]. In consequence, substrate atoms move back into posi- pied, nonbonding orbitals. In both cases, all Si atoms become more bulklike. tions they would occupy in a perfect bulk. The reconstruction of the clean surface is virtually We present experimental and theoretical evi- dence that this simplicity can be misleading. An undone. This behavior seems to be natural. Sb and As interplay between surface stress, dangling bond density, and chemical bond energies may force atoms are shallow substitutional donors, which means that the crystal perceives them as similar to substrate and adsorbate atoms into interstitial sites. This significantly affects positions of the native atoms. Nevertheless, their radius is larger subsurface atoms. We have observed such behavior and, when deposited on the surface, they do not for Sb on Si(113), a typical group V ‘‘surfactant’’ * Corresponding author. E-mail: jarek@ihp-ffo.de adsorbed on a surface [13] which is a limiting case 0039-6028/98/$ see front matter © 1998 Elsevier Science B.V. All rights reserved. PII: S0039-6028(98)00327-6