Silicides for the 65 nm Technology Node

摘要

At the 65 nm node, silicide faces formidable challenges. Co is the current process of record for most integrated circuit manufacturers and thus becomes baseline silicide for 65 nm. However, Ni is the likely replacement. Both silicides are challenged to meet the requirements at the 65 nm node. This manuscript reviews the current CoSi_2 challenges (dopant interactions, Ge interactions, linewidth extendibility, impurity effects, agglomeration issues, etc). Ni consumes less Si but has its own challenges, including issues with contact leakage and thermal budget, excessive diffusion and oxidation, interactions with dopant and impurities. Both silicides have formation and stability issues in the presence of Ge. Additions of Ge increase the temperature at which a low resistance CoSi_2 is formed due to film segregation into CoSi_2 and Ge-rich Si-Ge grains. With Ni, additions of Ge decrease the temperature at which NiSi converts to a NiSi_2, lead to agglomeration at a lower temperature and lead to germanosilicide formation.