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ABSTRACT: An energy parameterized pseudo-lucky electron model for simulation
of gate current in submicron MOSFET's is presented in this paper. The
model uses hydrodynamic equations to describe more correctly the carrier
energy dependence of the gate injection phenomenon. The proposed model
is based on the exponential form of the conventional lucky electron gate
current model. Unlike the conventional lucky electron model, which is
based on the local electric fields in the device, the proposed model
accounts for nonlocal effects resulting from the large variations in the
electric field in submicron MOSFET's. This is achieved by formulating
the lucky electron model in terms of an effective-electric field that is
obtained by using the computed average carrier energy in the device and
the energy versus field relation obtained from uniform-field Monte Carlo
simulations. Good agreement with gate currents over a wide range of bias
conditions for three sets of devices is demonstrated
IEEE Transactions on Electron Devices 09/1996; · 2.32 Impact Factor
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ABSTRACT: Two-dimensional energy-dependent substrate current models are
described for NMOS and PMOS devices that have been developed using a
multi-contour approach. The new models offer a significant improvement
in the calculation of substrate current due to a more accurate
calculation of the average energy as compared to the local-field model.
The models are implemented in a post-processing manner by applying a
one-dimensional energy conservation equation to each of many current
contours in order to generate a two-dimensional representation of
average energy and impact ionization rate, that is then integrated to
calculate the substrate current. The new models have been compared to
substrate current characteristics of a variety of NMOS and PMOS devices
for a wide range of bias conditions and channel lengths, and very good
agreement has been obtained with a single set of model parameters. An
additional significance of this work is the enhancement of the standard
multi-contour model by an energy-sink term that results in an improved
prediction of the impact ionization process in PMOSFET's
IEEE Transactions on Electron Devices 11/1994; · 2.32 Impact Factor
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ABSTRACT: Substrate current model based on the post-processing 1-D
hydrodynamic model attached to drift-diffusion simulators has proven to
be efficient and accurate for predicting substrate current for
contemporary submicron MOSFETs. However, as devices shrink into the deep
submicron regime, the self-consistent 2-D HD model will be increasingly
needed to predict not only the substrate current but also to accurately
determine the location of hot-carrier generation in evaluating the
reliability of competing device designs
Numerical Modeling of Processes and Devices for Integrated Circuits, 1994. NUPAD V., International Workshop on; 07/1994
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ABSTRACT: Based on the physical insights provided by the universal mobility
curve, an improved comprehensive universal model for effective electron
mobility in inversion layers of n-channel MOSFETs is developed for
circuit simulation. This model expresses the effective electron mobility
at room temperature as a function of effective vertical field. It
exhibits a high degree of accuracy for a wide range of different device
characteristics, such as channel doping levels, gate oxide thicknesses,
and channel dimensions. In addition, it predicts very well the effective
mobility under the effects of substrate biases for gate voltages well
above threshold, which is an improvement over earlier models. Moreover,
this model has been developed with an emphasis on the functional
dependence of mobility on high effective field, and is thus particularly
accurate in that range of effective field. This is a significant
advantage of the model since today's submicrometer MOSFETs typically
operate at high effective fields
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems 11/1993; · 1.27 Impact Factor
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ABSTRACT: Universal, semi-empirical MOSFET hole inversion layer mobility
degradation models for use in circuit simulation programs such as SPICE
are presented. By accurately predicting the mobility degradation due to
acoustic phonon scattering and surface roughness scattering for
p-channel MOSFETs at room temperature, these models eliminate the need
for fitting parameters for each technology, which is required in the
current SPICE level 3 model. The expressions reported accurately predict
the mobility over a very wide range of channel doping concentrations,
gate oxide thicknesses, gate voltage, and substrate bias, and they agree
very well with recently published experimental mobility degradation
data. When implemented in a circuit simulation code, these models will
accurately determine the channel mobility in surface p-channel MOSFETs
using only the channel doping concentration, gate oxide thickness,
substate bias, and applied gate drive voltage as input parameters
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems 04/1993; · 1.27 Impact Factor
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ABSTRACT: A multicurrent contour, average-energy-based, substrate current model for silicon submicrometer NMOSFETs is presented as a significant improvement to the local-field model that is commonly used in modern drift-diffusion device simulators. The model is implemented as a post-processor by applying a one-dimensional energy conservation equation to many current contours in order to generate a two-dimensional representation of average energy and impact ionization rate which is integrated to calculate the substrate current. Comparisons of simulations and experimental I-V curves for both simple and LDD MOSFETs are presented. Outstanding agreement has been obtained over a wide range of bias conditions and channel lengths.< >
IEEE Electron Device Letters 12/1992; · 2.85 Impact Factor
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ABSTRACT: Summary form only given. The authors present a more rigorous
hydrodynamic postprocessing approach than that implemented by J.W.
Slotboom et al. (1991). The proposed model is 2-D and is based on the
1-D form of energy equation described by R.K. Cook et al. (1982),
implemented into the 2-D drift-diffusion simulator PISCES as a
postprocessor to calculate substrate current. This new approach involves
the determination of the average energy along many current contours
using the 1-D energy conservation equation and the local electric fields
calculated by PISCES along each current path. The impact ionization
rates are calculated using an energy parameterized form of the Chynoweth
law. These coefficients along with the current densities calculated by
PISCES are then used to determine the 2-D distribution of generation
rates, and the generation rates are integrated over the entire 2-D
device structure to calculate the substrate current. The authors have
demonstrated very good agreement with substrate current characteristics
measured on a broad range of LDD (lightly doped drain) NMOSFET devices
with varying channel lengths, gate biases, and drain biases
IEEE Transactions on Electron Devices 12/1992; · 2.32 Impact Factor
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Device Research Conference, 1992. Digest. 50th Annual; 07/1992
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ABSTRACT: Relaxation time models found in most hydrodynamic device simulators fail in the presence of abruptly decreasing electric fields. Such fields are encountered at MOSFET drain junctions and lead to carrier distribution functions composed of two distinct populations: one hot and one cold. An approach which expresses features of both populations and produces more accurate simulation results is presented.
Electronics Letters 07/1992; · 0.96 Impact Factor
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ABSTRACT: A comprehensive model of effective (average) mobility and
local-field mobility for holes in MOSFET inversion layers is presented.
The semiempirical equation for effective mobility, coupled with the new
local-field mobility model, permits accurate two-dimensional simulation
of source-to-drain current in MOSFETs. The model accounts for the
dependence of mobility on transverse and longitudinal electric fields,
channel doping concentration, fixed interface charge density, and
temperature. It accounts not only for the scattering by fixed interface
charges, and bulk and surface acoustic phonons, but it also correctly
describes screened Coulomb scattering at low effective transverse fields
(near threshold) and surface roughness scattering at high effective
transverse fields. The model is therefore applicable over a much wider
range of conditions compared to earlier reported inversion layer hole
mobility models while maintaining a physically based character
IEEE Transactions on Electron Devices 02/1991; · 2.32 Impact Factor
