Titanium Silicide/Titanium Nitride Full Metal Gates for Dual-Channel Gate-First CMOS

We demonstrate a thermally stable titanium silicide/titanium nitride (TiSi
_x
/TiN) full metal gate (FMG) for dual-channel gate-first high-
$k$
/metal gate complementary metal–oxide–semiconductor technology. Unlike prior tungsten-based FMG, the simple TiSi
_x
/TiN gate electrode does not require any additional barrier layer preventing oxygen down-diffusion during high-temperature processing, as the TiSi
_x
itself blocks oxygen. With HfO
₂
-based gate dielectrics and without any oxygen scavenging scheme, we thus demonstrate a capacitance-equivalent thickness in inversion (
$T_{\mathrm {inv}})$
of 1.11 nm, corresponding to an equivalent oxide thickness of
$\sim 0.7$
nm. Silicon channel nFET and silicon germanium channel pFET parametrics are similar to those of control devices utilizing a conventional a-Si/TiN metal-inserted poly-Si stack (MIPS) gate, while providing superior gate sheet resistance. By supplanting MIPS with such an FMG, we anticipate that contacted gate pitch can be scaled aggressively via reduced gate height and borderless source/drain contacts.