Clarification of Additional Mobility Components associated with TaC and TiN Metal Gates in scaled HfSiON MOSFETs down to sub-1.0nm EOT

To clarify mobility (μ) limiting factors in aggressively scaled metal gate (MG)/high-k insulator (HK) MOSFETs, additional μ components associated with TaC and TiN MGs and their physical origins are investigated. With a TaC/HfSiON stack, μ
_@Eeff=1MV/cm
of 215cm
²
/Vs, 87% of Poly Si/SiO
₂
universal, at EOT of 0.91nm is achieved. Two different types of additional scattering are, for the first time, identified; the one is remote Coulomb scattering (RCS) by the charges near the HK-IL interface, induced by diffused metals, and the other becomes obvious near sub-1.0nm-EOT region, plausibly originating from defects near the MG-HK interface.