Subthreshold Performance of Dual‐Material Gate CMOS Devices and Circuits for Ultralow Power Analog/Mixed‐Signal Applications

In this chapter, the analog performance of 100 nm dual‐material gate complementary metal oxide‐semiconductor (DMG CMOS) devices in the subthreshold regime of operation is reported. The analog performance parameters, namely transconductance
g

_m
, transconductance generation factor
g

_m
/
I

_D
, Early voltage
V

_A
, output resistance
R

_o
, and intrinsic gain for the DMG n‐MOS (metal oxide‐semiconductor) devices, and
V

_A
and
R

_o
for the DMG p‐MOS devices are investigated systematically with the help of extensive device simulations. The effects of different capacitances on the unity‐gain frequency
f

_T
are also studied. The DMG CMOS devices are found to have significantly better performance as compared to their single‐material gate (SMG) counterparts. More than 70% improvement in the voltage gain is observed for the CMOS amplifier when DMG, instead of SMG, is used for both the n‐ and p‐channel devices.