Characteristic of the Si(100) Surface Low-Temperature Phase with Two Competing Structures Investigated by Rare Gas Adsorption

The change of the Si(100) surface, exposed to Kr gas at 10 K with the scanning tunneling microscopy (STM) tip being extracted, was observed by STM. For a n-type sample, a p(2 x 2)/c(4 x 2) coexisting structure was stably observed even at low Kr coverage, and the amount of the c(4 x 2) area increased with increasing the coverage. These results clearly show the appearance of the p(2 x 2) phase at 10 K. The Kr growth process was observed by low-energy electron diffraction measurement for both n- and,p-type samples, suggesting the influence of the STM measurement on the c(4 x 2) structure observed for the p-type sample at 10 K.