Medium-energy ion scattering (MEIS) measurements have been performed on the Si(111) surface which was terminated with hydrogen by means of immersion in a diluted HF solution. The measurements and the fit of Monte Carlo simulations to the experimental data show that the structure of the Si(111):H surface is close to that of a truncated bulk Si lattice. The relaxation of the distance between the top and the second layer, dl2, and that between the second and the third layer, d23, are as small as 0.00 + 0.04 Å (0.0 + 5.1%) and - 0.04 + 0.04 Å (—1.7 + 1.7%), respectively. The measurements further reveal that the average one-dimensional root-mean-square thermal displacement of the two outermost atomic layers is enhanced from the bulk value of 0.075 Å to 0.11+ 0.01 Å.

Surf. Sci.

Nishiyama, A, ter Horst, G, Lohmeier, M, Molenbroek, A. M, & Frenken, J. W. M. (1994). Structure analysis of the HF-treated Si(111): H surface with medium-energy ion scattering. Surf. Sci., 321, 261–266.