Initial stage of Si(111)-B surface reconstruction studied by scanning tunnelling microscopy

Abstract Scanning tunnelling microscopy has been used to study the interaction of elemental B with Si(111) 7×7 surface. Elemental B is evaporated at desired temperature (room temperature (RT), 800–1000°C), and the amount of B is varied with the evaporation time. The shapes and structures of the reconstructed areas are only dependent on B coverages. The reconstructed areas which mostly consist of the two types of ring structures (bright ring and dark ring) are formed in very small B coverage. When larger amount of B is evaporated, the reconstructed areas containing a mixture of various adatom structures such as 3 × 3 R30° , 2×2, c(4×2) and the two types of ring structures are formed. These areas grow larger over the surface in proportion to the amount of B until overall of the surface changes to these areas. When much more B is evaporated, the number of the 3 × 3 R30° unit cells increases in these reconstructed surface and well-ordered 3 × 3 R30° surface is formed finally.