Determination of anisotropic diffusion ratio on Si(110)-162

Yano, Masahiro   ; Terasawa, Tomoo   ; Yasuda, Satoshi   ; Machida, Shinichi*; Asaoka, Hidehito  

The anisotropic diffusion coefficient ratio of the Si atoms on the Si(110)-162 reconstructed structure is determined by observing the "void" by scanning tunneling microscope (STM). The void length was measured to evaluate the anisotropic growth rate ratios for each void depth. The anisotropy of the void shape decreased as the void became deeper, indicating the reduction of the Si density ratio during the diffusion on the sidewall. Taking the migration of diffusing Si atoms to the upper and lower terraces and the adjacent sidewalls into account, we determined that the diffusion coefficient in the direction along the [12] or [12] parallel to the step rows of the 162 reconstructed structure is 3.0 times higher than that of the other direction.