1999 年 20 巻 12 号 p. 859-864
Using ultrahigh vacuum scanning electron microscopy, we investigated the transformation processes of holes and hillocks on vicinal Si(111) surfaces during annealing at around 1200°C. A hole and a hillock decay symmetrically with one another, their shapes are complementary and the decay rate is almost the same except during the final stage, where hillocks decay faster than holes. Flat (111) planes appear both at the bottom of the hole and at the top of the hillock due to layer-by-layer decay. As a result of transformation, regularly arranged atomic-step bunches are formed in both cases. The electric field used for sample heating was found to greatly affect the final shape of step bunches. As for the transformation of holes, step-flow sublimation becomes the dominant process for holes larger than the adatom diffusion length, while layer-by-layer filling-in of the bottom terrace is the dominant process for holes smaller than the adatom diffusion length.