A novel use of Ti marker is introduced to investigate the moving species during Pd2Si formation on ⟨111⟩ and ⟨100⟩ Si substrates. Silicide formed from amorphous Si is also studied using a W marker. Although these markers are observed to alter the silicide formation in the initial stage, the moving species can be identified once a normal growth rate is resumed. It is found that Si is the dominant moving species for all three types of Si crystallinity. However, Pd will participate in mass transport when Si motion becomes obstructed. off