Ion mixing of near-noble monosilicides with Si substrates

Abstract

Xe ion irradiation of NiSi, PdSi, and PtSi on Si was performed at various substrate temperatures. The phase formation and mixing behavior of the three monosilicides with their Si substrates are quite different. For NiSi, NiSi2 was formed on amorphous Si substrates at 350 °C, while NiSi remained stable on crystalline Si substrates even at 400 °C. PtSi reacted with Si to form a metastable Pt4Si9 phase, which decomposed back to PtSi and Si by successive irradiation at higher temperatures. The decomposition of the metastable Pt4Si9 was easier on crystalline Si substrates than on amorphous substrates. No mixing was observed for PdSi on Si in the temperature range of 35–400 °C. The ion mixing results were compared with those from thermal annealing. The importance of demixing of a thermally stable system was explored.