Mechanism of nickel disilicide growth caused by RIE plasma-induced damage on silicon substrate

Effects of dry-etching damage at the surface of p-type silicon on pyramidal spike growth of nickel disilicide (NiSi₂) were investigated by using sheet resistance (Rs) measurement, cross sectional SEM7TEM, UV Raman spectroscopy and elastic recoil detection analysis (ERDA), and as a result, a model for nickel diffusion induced by vacancies was proposed. According to this model, the pyramidal spike shape growth of NiSi₂ is enhanced by vacancies in silicon substrate generated by H ions projected during reactive ion etching (RIE). To confirm this model, Si ions were implanted prior to nickel deposition instead of RIE process, and the vacancies with the same depth in silicon substrate as those caused by H⁺ ions during RIE were generated. The Rs increase of NiSi was successfully reproduced by this Si ion implantation technique. Then, it is concluded that pyramidal spike growth of MS12 is caused by the vacancies generated by H ion projected during RIE process before nickel silicidation.