Abstract—Parasitic series resistances and mobility degradation
are limiting the development of advanced MOSFETs. We review,
scrutinize, and critically compare five parameter extraction
methods that use DC data measured from a single test device.
The use of a single device facilitates individual characterization
and avoids the impact of device-to-device model parameter
variation that affects other common methods that require using
measurements from arrays of transistors with several different
geometries.
Index Terms— MOSFET, parameter extraction, Mobility
degradation, Parasitic series resistance.
I. INTRODUCTION
HE presence of source-and-drain series resistance and
mobility degradation in MOSFETs produce similar effects
on their drain current-gate voltage ID(VGS) transfer
characteristics. Various specialized books and review articles
have explained and analyzed this topic [1-10], and several
procedures have been proposed and reported to extract the
values of the parameters that correspond to these two effects
in MOSFET compact models [11-35]. We recently published a
novel method that allows extracting the total series resistance
and the mobility degradation of a single test device from DC
measurements [34]. We have also described and critically
reviewed several of the diverse methods that exist for
extracting the values of these two important model parameters
for MOSFET functional description [4,10].
We will examine here five methods for extracting the
values of the series resistance and the mobility degradation
parameters of MOSFET models that use drain current-gate
voltage ID(VGS) transfer characteristics and drain current-drain
A. Ortiz-Conde, F. J. García-Sánchez, and A. Sucre-González are with the
Solid State Electronics Laboratory at Universidad Simón Bolívar, Caracas,
Venezuela (ortizc@ieee.org; fgarcia@ieee.org; andresucre88@gmail.com).
R. S. Murphy-Arteaga, R. Torres-Torres, and Fabián Zárate-Rincón are
with the Electronics Department at the Instituto Nacional de Astrofísica,
Óptica y Electrónica (INAOE), Tonantzintla, Puebla 72840, México
(rmurphy@inaoep.mx ; reydezel@inaoep.mx; fabian_zar@hotmail.com ).
Juin J. Liou is with EMOAT, LLC, 1933 Ayrshier Place., Oviedo, FL
32765, USA ( juin.liou@hotmail.com ).
978-1-5386-1962-9/17/$31.00 ©2017 IEEE
voltage ID(VDS) output characteristics measured from a single
test device.
II. PARAMETER EXTRACTION METHODS
The above-threshold drain current of MOSFETs operating
in the so-called triode region may be essentially modeled in
general by a simple equation of the form [22]:
2
ds
D eff ox gs T ds
eff
V W
= C V V V
I
L
μ
- -
, (1)
where W is the channel width, Leff is the effective channel
length, μeff is the Vgs-dependent effective mobility, COX is the
gate dielectric capacitance, VT is the threshold voltage, and the
device’s intrinsic gate-to-source, Vgs, and drain-to-source, Vds,
voltages are related to their external counterparts by:
2
gs GS D
R
V V I = - , (2)
ds DS D
V V RI = - , (3)
where VGS is the externally applied gate voltage, VDS is the
externally applied drain voltage, R is the total source-and-
drain series resistance. In writing (2) and (3), the drain and
source resistances are assumed equal (R/2). Possible
asymmetry between the drain and the source, giving rise to
different values of drain and source resistances, can be an
important aspect to consider in modern devices and it has been
recently studied in [10].
The Vgs-dependent degradation of the effective mobility is
frequently modeled by an expression of the form [36]:
( ) ( )
2
1 2
1
o
eff
gs T gs T
=
V V V V
μ
μ
θ θ + - + -
(4)
where μo is the low-field mobility, θ1 and θ2 are the first and
second order gate field (Vgs) mobility degradation factors. A
commonly used first order (θ2=0) simplified version of (4) is:
( )
1
1
o
eff
gs T
=
V V
μ
μ
θ + -
. (5)
Substitution of (4) into (1) yields:
( ) ( )
( )
2
1 2
2
1
ds
o gs T ds
D
gs T gs T
V
K V V V
=
I
V V V V θ θ
- -
+ - + -
, (6)
On the extraction methods for MOSFET series
resistance and mobility degradation using a
single test device
Adelmo Ortiz-Conde, Senior Member, IEEE, Andrea Sucre-González, Fabián Zárate-Rincón,
Reydezel Torres-Torres, Senior Member, IEEE, Roberto S. Murphy-Arteaga, Senior Member, IEEE,
Juin J. Liou, Fellow Member, IEEE, and Francisco J. García-Sánchez, Senior Member, IEEE
T
2017 International Caribbean Conference on Devices, Circuits and Systems (ICCDCS)
15