Phase diagrams and metal-rich silicide formation

Abstract

Phase formation at temperatures well below the melting point of the phases was studied in thin silicon–near‐noble‐metal films by means of ⁴He⁺ ion‐backscattering spectrometry and x‐ray diffractometry in SiO₂/Si/M film systems, where the metal‐film thickness was larger than that of the Si film. In the initial stage of compound formation where both unreacted Si and M layers are present, the M₂Si phase has been found. At increasing annealing times and temperatures, more and more metal‐rich phases have been detected. The Si‐Ni thin‐film system evolution follows exactly the phase diagram reported in the literature; moreover, for Ni, Pt, and Pd‐Si thin‐film interactions the end phases are dictated by the phase equilibrium and can be predicted by the phase diagrams.