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SOISPICE-5.0
UFSOI Silicon-On-Insulator MOSFET Models
Introduction to User's Guide: UFSOI Model Description
SOISPICE-5.0 (an enhanced version of Spice2)
contains the versions of the process/physics-based UFSOI
MOSFET models that were released in January 2000. (Later versions are released only
in the UFSOI/API/Spice3 program.) The models are charge-based with five terminals, and have
a floating-body option. The model for the fully depleted (FD) device properly
accounts for the charge coupling between the front and back gates, and includes
a two-dimensional analysis of the electrostatic potential in the SOI film
and underlying BOX for subthreshold-region operation. The model assumes
that the film is strongly FD, except in and near the accumulation region
where it accounts for the majority-carrier charge, and hence dynamic floating-body
effects. The non-fully depleted (NFD, which in later releases is evolved to UFPDB)
device model properly accounts for
DC as well as dynamic floating-body effects defined by capacitive coupling
and carrier recombination/generation. Both models include an optional quasi-2D
accounting for the (coupled) parasitic BJT (current and charge), which can
be driven in the floating-body mode by transient body charging current and/or
generation current, including that due to impact ionization which is characterized
by a non-local, carrier temperature-dependent model for the ionization rate
integrated across the channel(s), (optional) LDD, and drain. The charge
modeling has been recently upgraded; all terminal charges (including MOS
and bipolar components) and their derivatives are continuous for all bias
conditions. Substrate depletion charge under the source and drain regions,
which becomes important when the BOX is scaled, is included as components
of source, drain, and back-gate charge. Temperature dependence for both
models is also implemented, without the need for any additional parameters,
as is physics-based noise modeling for AC simulation, which accounts for
thermal noise from the channel and parasitic series resistances, shot noise
at the source and drain junctions, and flicker noise in the channel. The
temperature-dependence modeling is the basis for a self-heating option,
which uses special iterate control for the local device temperature node
that yields good convergence even for large circuits.
Because of the process basis of the models,
parameter evaluation can be based in part on device structure, and hence
can be done unequivocally, avoiding self-heating and pulsing (floating-body)
problems in the needed data acquisition. Both the FD and NFD models have
been extensively exercised and refined in DC, transient, and AC device
and circuit simulations. The User's Guide describes the use of the UFSOI
models in SOISPICE-5.0, and includes citations of papers and reports that
detail the physical modeling. The Guide is written as a supplement to
the original "SPICE Version 2G User's Guide" from the University of California,
Berkeley.
The executable file (soispice5.0) can be
downloaded by clicking "Download Software". The tar
file to be downloaded
includes simulation examples, postscript files of the User's Guide and
a report on process-based UFSOI parameter evaluation, and the University
of Florida (and UCB) COPYRIGHT statement.
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