[13p-4E-1~20] 6.5 Surface Physics, Vacuum

[13p-4E-7] Stress measurement of Si(111)7×7 reconstruction during atomic hydrogen adsorption

〇YUKI UOZUMI^1,2, HIDEHITO ASAOKA¹ (1.JAEA ASRC, 2.Hitachi Power Solutions)

Keywords:atomic hydrogen,H-termination,surface stress

We have succeeded in measurements of the surface stress in Si(111) as a function of 7×7 reconstruction by comparison with the H-terminated Si(111)1×1 surface. In order to obtain information on both the surface stress and the surface reconstruction simultaneously, we have combined the surface-curvature and the reflection-high-electron-energy-diffraction instrumentations in an identical ultrahigh vacuum system. The stress evolution shows a decrease of tensile stress corresponding to the formation of H-termination at the beginning of the atomic hydrogen exposure of Si(111)7×7 surface. After the above treatment, a complete transformation of the surface structure occurs from the reconstructed surface to the 1×1 one. As a result, we find the Si(111)1×1 surface releases 1.7 N/m (=J/m2), or (1.4 eV/(1×1 unit cell)), of the surface energy from the strong tensile Si(111)7×7 reconstruction.