Quantization of terrace widths on vicinal Si(111)

Scanning tunneling microscope (STM) and high resolution low‐energy electron diffraction studies of slowly cooled Si(111) surfaces misoriented by 1.3° towards the [1̄1̄2] direction show the existence of a preferred displacement of the (7×7) reconstruction across single‐layer steps. STM results show that this correlation is quite strong: it occurred in 42 of the 46 steps observed. The correlation leads to a quantization of the terrace widths to units of the (7×7) unit cell. Less extensive results on the 6° misoriented surface suggest that the (7×7) reconstruction is also correlated across triple‐layer steps.