ROOM-TEMPERATURE GROWTH OF SUBMONOLAYERS OF SILICON ON SI(001) STUDIED WITH SCANNING-TUNNELING-MICROSCOPY

Room-temperature deposited submonolayers of silicon on Si(001) are inv estigated using STM. The observed structures and the mechanisms leadin g to their formation are discussed. Isolated ad-dimers in different et ries are described and a kinetic model for their formation is deduced. It is shown how further growth occurs via the formation of 3-atom clu sters, which act as nucleation centers for the formation of two types of Linear structures. One of the line types is formed in the [110] dir ection, and has been observed before. The other is in the [310] direct ion. At a coverage of nearly 0.2 ML a kind of random network consistin g 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 pathw ay for this conversion is proposed on the basis of experimental observ ations.