ATOMIC-STRUCTURE OF SI(111) (SQUARE-ROOT-3XSQUARE-ROOT-3) R30-DEGREES-B BY DYNAMIC LOW-ENERGY ELECTRON-DIFFRACTION

The geometric structure of Si(111) (3»×3») R30°-B formed by annealing highly doped Si(111) samples was determined by low-energy electron diffraction. The optimal structure has the B atom occupying a substitutional B5 site, different from adatom sites occupied by other group-III metals. Three-dimensional atomic coordinates and surface bond lengths have been determined. With B at the B5 site, the compressive stress between Si and B atoms disappeared in the near surface region. The difference between an all Si 3 reconstruction structure stabilized by B doping with another structure observed by Ag doping is discussed. © 1990 The American Physical Society.