Variability Origins of Parasitic Resistance in FinFETs With Silicided Source/Drain

Origins of parasitic resistance
R
_para
fluctuation were investigated by a measurement-based analysis for fin-shaped FETs (FinFETs) with NiSi in the source/drain (S/D). Fluctuation in the extension resistance
R
_ext
reflecting fin thickness
T
_fin
fluctuation is negligible for the sufficiently small thickness of the sidewall spacer. Although the NiSi incorporation in the S/D reduces
R
_para
on average, it causes additional fluctuation of
R
_para
. Analyzing the correlation of the
R
_para
fluctuation with the fluctuation in
T
_fin
and the lateral growth of NiSi, the dominant origin of the
R
_para
fluctuation is specified to be the NiSi/n
⁺
-Si contact resistance.