Selectively enhanced silicide formation by a gold interlayer: Probing the dominant diffusing species and reaction mechanisms during thin-film reactions

Formation of silicides in the presence of a thin gold interlayer is studied, making use of the rapid outdiffusion of Si through gold. With Si being the dominant diffusing species, an enhanced rate is expected, as observed for PtSi, Fe3Si, CoSi, and MoSi2. No enhancement is expected when metal is the dominant diffusing species, in agreement with the results on Pt2Si, Co2Si, and Ni2Si. Such studies thus provide valuable information regarding reaction mechanisms.