Nanoscale MOSFET Modeling:
Part 1: The Simplified EKV Model for the Design of Low-Power Analog Circuits
C. Enz, F. Chicco and A. Pezzotta
in IEEE Solid-State Circuits Magazine, vol. 9, no. 3, pp. 26-35, Summer 2017
doi: 10.1109/MSSC.2017.2712318
Abstract: This article presents the simplified charge-based Enz-Krummenacher-Vittoz (
EKV) [11] metal-oxide-semiconductor field-effect transistor (MOSFET) model and shows that it can be used for advanced complementary metal-oxide-semiconductor (CMOS) processes despite its very few parameters. The concept of an inversion coefficient (
IC) is first introduced as an essential design parameter that replaces the overdrive voltage V
G-V
T0 and spans the entire range of operating points from weak via moderate to strong inversion (
SI), including the effect of velocity saturation (
VS). The simplified model in saturation is then presented and validated for different 40- and 28-nm bulk CMOS processes. A very simple expression of the normalized transconductance in saturation, valid from weak to
SI and requiring only the
VS parameter
mc, is described. The normalized transconductance efficiency
Gm/ID, which is a key figure-of-merit (FoM) for the design of low-power analog circuits, is then derived as a function of
IC including the effect of
VS. It is then successfully validated from weak to
SI with data measured on a 40-nm and two 28-nm bulk CMOS processes. It is then shown that the normalized output conductance
Gds/ID follows a similar dependence with
IC than the normalized
Gm/ID characteristic but with different parameters accounting for drain induced barrier lowering (DIBL). The methodology for extracting the few parameters from the measured
ID-VG and
ID-VD characteristics is then detailed. Finally, it is shown that the simplified
EKV model can also be used for a fully depleted silicon on insulator (FDSOI) and Fin-FET 28-nm processes [
read more...]
FIG: The simplified EKV model applied to a 28-nm FDSOI CMOS process:
Gm n UT / ID versus IC for three different transistor channel lengths
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