Real-Time Observation of Ti Silicide Epitaxial Islands Growth with the Photoelectron Emission Microscopy

The formation of nanoscale Ti silicide islands was observed by Photo-electron emission microscopy (PEEM). The islands were prepared by deposition of an ultrathin Ti (3–12ML) on Si(001) at room temperature and at an elevated temperature of 950°C. The island formation was initiated by in situ annealing to 1150° C. It was observed that initially Ti silicide islands form while longer annealing indicates some islands move and coalesce with other islands. Most of the islands are similar in size and have relatively uniform separation. Also, it was shown that for continued Ti deposition at a temperature of 950°C, the density of islands did not increase. However, islands grew together when their perimeter lines touch each other. The results are described in terms of island growth processes of coalescence and ripening.