Co 2Si, CrSi 2, ZrSi 2 and TiSi 2 formation studied by a radioactive 31Si marker technique

Abstract

Radioactive 31Si (half-life, 2.62 h) was used as a marker to study Co 2Si, CrSi 2, TiSi 2 and ZrSi 2 formation. By marking the initial layer of silicide with radioactive silicon atoms and by measuring the activity profile in the silicide layer after further silicide formation, the dominant diffusing species and its mechanism of diffusion during the formation of these silicides could be determined. For Co 2Si it was found that cobalt is the diffusing species, while disilicide formation was found to take place by silicon substitutional (vacancy) diffusion, with a high self-diffusion coefficient.