Statistical demonstration of silicide-like uniform and ultra-low specific contact resistivity using a metal/high-k/Si stack in a sidewall contact test structure

We demonstrate a 300mm wafer scale conformal contact process to achieve uniform ultra-low specific contact resistivity (ρ
_c
) for metal/high-k/n
⁺
Si (MIS) contacts. To achieve conformal contacts, we use a sidewall TLM (STLM) test structure that helps to minimize current crowding effect and variability. A systematic study is provided by varying doping density (N
_D
), high-k material (LaO
_x
, ZrO
_x
and TiO
_x
) and high-k thickness (t
_d
) to optimize ρ
_c
. The obtained ρ
_c
and its uniformity are found to be comparable with standard nickel silicide technology, with a possibility of further improvement by use of lower work-function metal.