Source/Drain Extension Region Engineering in FinFETs for Low-Voltage Analog Applications

In this letter, we propose a novel design methodology for engineering source/drain extension (SDE) regions to simultaneously improve intrinsic dc gain (A
_VO
) and cutoff frequency (f
_T
) of 25-nm gate-length FinFETs operated at low drain-current (I
_ds
=10 muA/mum). SDE region optimization in 25-nm FinFETs results in exceptionally high values of A
_VO
(~45 dB) and f
_T
(~70 GHz), which is nearly 2.5 times greater when compared to devices designed with abrupt SDE regions. The influence of spacer width, lateral source/drain doping gradient, and the spacer-to-gradient ratio on key analog figures of merit is examined in detail. This letter provides new opportunities for realizing future low-voltage/low-power analog design with nanoscale SDE-engineered FinFETs