Room-temperature growth of submonolayers of silicon on Si(001) studied with scanning tunneling microscopy

Abstract
Room-temperature deposited submonolayers of silicon on Si(001) are investigated using STM. The observed structures and the mechanisms leading to their formation are discussed. Isolated ad-dimers in different geometries are described and a kinetic model for their formation is deduced. It is shown how further growth occurs via the formation of 3-atom clusters, which act as nucleation centers for the formation of two types of linear structures. One of the line types is formed in the [110] direction, and has been observed before. The other is in the [310] direction. At a coverage of nearly 0.2 ML a kind of random network consisting of segments of the two types of atomic lines is formed. Above 0.2 ML coverage these lines are converted into epitaxial dimer rows. A pathway for this conversion is proposed on the basis of experimental observations.