Monte Carlo simulation of decay process of pyramidal islands formed on Si(1 0 0) surface

Decay of pyramidal islands formed on Si(1 0 0) surface has been analysed by using a Monte Carlo simulation based on a modified solid-on-solid model. An atom on the surface is more stable when it sticks an island to form a dimer and a dimer row, which results in a rectangular island elongated along the dimer row direction. The decay process is primarily determined by atom migration from step edges of the islands to the outer terrace, especially from a biatomic height Db step. The elongation of an island changes during the decay as the migration front changes from Db step to Sa step. In the final stage of the decay of the topmost layer, an island elongated along the dimer row is formed before the complete disappearance of the layer. This is an essential process for the decay of one layer in an island on Si(1 0 0).