Interaction of copper metallization with rare-earth metals and silicides

Solid-phase reactions of copper films with underlying gadolinium, erbium, a nd erbium-silicide layers on Si(100) substrates were investigated. For the phase analysis, x-ray diffraction and cross-sectional transmission electron microscopy were used. In the case of Cu/Gd/Si(100), an orthorhombic GdSi2 formed, and, at higher temperatures, copper aggregated into islands. Anneal ed Cu/Er/Si(100) samples resulted in a hexagonal Er5Si3 phase. In the Cu/Er Si2-x/Si system, the copper catalyzes the transformation of the highly orie nted hexagonal ErSi2-x phase into hexagonal Er5Si3. Diverse phase developme nts of the samples with Gd and Er are based on reactivity differences of th e two rare-earth metals. (C) 2001 American Institute of Physics.