Low temperature epitaxial NiSi2 formation on Si(111) by diffusing Ni through amorphous Ni–Zr

Abstract

Although amorphous alloys are known to be good diffusion barriers, amorphous nickel-zirconium is shown to react with Si at relatively low temperatures. Diffusion of Ni at 350°C through an amorphous Ni–Zr buffer layer leads to the formation of epitaxial NiSi₂ on single crystal silicon substrates. Interplay of mobility and thermodynamics is applicable for epitaxial silicide nucleation and growth. Also, a one-step annealing process in oxygen ambient leads to bilayer formation of NiSi₂/ZrO₂ structures on silicon substrates.