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

摘要

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 SEM/TEM, 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 NiSi2 is caused by the vacancies generated by H+ ion projected during RIE process before nickel silicidation.