Metallization-induced spontaneous silicide formation at room temperature: The Fe/Si case

Abstract

The composition of the interface resulting from the room-temperature deposition of iron on Si(100) under ultrahigh-vacuum conditions has been monitored by surface-sensitive techniques such as Auger electron spectroscopy, low-energy electron diffraction, and photoemission spectroscopy with synchrotron radiation. The results show unequivocally that the Fe/Si interface is not abrupt, but rather an amorphous intermixed region with composition close to Fe3Si. The formation of this silicidelike layer is related to the metallization of the deposited Fe overlayer. Upon annealing a thick film of Fe, we demonstrate that Fe3Si is the first phase to nucleate, in opposition to standard models that point to FeSi as the first silicide formed.