The size changes of stacking-fault half-units of dimer-adatom stacking-fault structures were investigated by means of high-temperature scanning tunnelling microscopic observations of (111) surfaces which were quenched from temperatures of 380 to 500C. A large number of successive scanning tunnelling microscopic images clearly showed that a stacking-fault half-unit changed only to a one-size, larger or smaller, half unit. The appearance and disappearance of a stacking-fault half-unit always occurred via the stacking-fault half-unit with the smaller size. The results could be explained in terms of a model in which the stacking-fault region expanded or contracted via the 1-by-1 movement of Si atoms to the stacking-fault or to unfaulted sites which were associated with new dimer formation or destruction during size changes. The activation energy for the size-change process was deduced to be equal to 1.8eV for a (7 x 7) stacking-fault to (9 x 9) stacking-fault transition, and equal to 2.0eV for a (9 x 9) stacking-fault to (7 x 7) stacking-fault transition.

Size Changes of n x n Stacking-Fault Half Units of Dimer-Adatom Stacking-Fault Structures on Quenched Si(111) Surfaces T.Ishimaru, K.Shimada, T.Hoshino, T.Yamawaki, I.Ohdomari: Physical Review B, 1999, 60[19], 13592-7