Direct stress measurement of Si(111) 77 reconstruction

Asaoka, Hidehito  ; Yamazaki, Tatsuya; Yokoyama, Yuta; Yamaguchi, Kenji

We have focused on stress measurements of the reconstructed Si(111) 77 and the H-terminated Si(111) 11 surfaces. In order to obtain information on both the surface stress and the surface structure simultaneously, we have combined the surface-curvature and the reflection-high-electron-energy-diffraction instrumentations in an identical ultrahigh vacuum system. At the beginning of Ge wetting layer growth on H-terminated Si(111), the stress gradient drastically changes accompanied by change in the surface structure resulting from the H desorption. Comparison of the surface stress behaviors between Ge wetting layer growth on the H-terminated Si(111) 11 and the Si(111) 77 surfaces reveals that the Si(111) 11 surface releases 1.6 N/m (=J/m), or (1.3 eV/(11 unit cell)), of the surface energy from the strong tensile Si(111) 77 reconstruction.