Low-temperature formation of CoSi2 in the presence of Au

The formation of cobalt silicides was studied in the presence of interlayers and capping layers of Au, using both ex situ and in situ characterization techniques. The formation temperature of CoSi2 was found to be significantly lowered in the presence of Au. Two regimes can be discerned. For thin interlayers or capping layers, Au does not significantly affect the formation of Co2Si and CoSi, while it lowers the nucleation temperature of CoSi2. For thick interlayers, CoSi2 appears to form as the first phase at temperatures as low as 300 degreesC. The results are discussed within the context of classical nucleation theory and known models for phase selection during solid-state reactions. (C) 2004 American Institute of Physics.