| Abstract |
| Severe resistivity size effect in Cu interconnects is attributed to the relatively long bulk electron mean free path (39 nm at 298 K), which is inherently determined by phonon scattering. In this regard, Ru and Co have been recently considered as attractive alternatives for next-generation interconnect materials because the significantly shorter electron mean free paths for Ru (6.6 nm) and Co (11.8 nm) have been predicted to lead to a dramatically reduced resistivity size effect, which may allow lower resistivity of these materials than Cu at sufficiently reduced interconnect dimensions despite their relatively high bulk resistivies. In this study, the impact of surface and grain boundary scattering for Ru and Co was assessed based on the Fuchs-Sondheimer surface scattering model and the Mayadas-Shatzkes grain boundary scattering model, first by fitting these models to the resistivity data reported in the literature and second by artificially varying the scattering parameters in the models. The results predict that the wire resistivities of Ru and Co will cross below that of Cu at wire-widths of 10-15 nm.
(Received June 4, 2018; Accepted June 25, 2018) |
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| Key Words |
| ruthenium, cobalt, interconnects, resistivity size effect, electron mean free path |
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