Determination of the Diffusing Species and Diffusion Mechanism during CoSi , NiSi , and PtSi Formation by Using Radioactive Silicon as a Tracer

Abstract

Information about the diffusing species and the mechanisms of diffusion during second‐phase formation of ,, and was obtained by using radioactive 31Si as a tracer. The position of the radioactive silicon tracer was determined after silicide formation by using sputter depth profiling and radioactivity measurement, the amount of silicide removed during sputtering being determined by Rutherford backscattering spectrometry of alpha particles. The metal was found to diffuse during growth, while Si appeared to be the dominant diffusing species for and formation. Radioactive silicon used as a tracer can also give information regarding the diffusion mechanisms occurring during silicide formation if silicon is the diffusing species. It was concluded that transformation of predominantly takes place by silicon grain boundary diffusion, whereas formation from apparently occurs by a combination of silicon grain boundary and silicon vacancy diffusion.