The previous versions
of Minimos-NT provided only
two simulation modes: the
basic steady-state DC mode and the transient simulation mode that takes
all
time derivatives in the time domain into account. Using the transient
mode
small-signal analysis is very inconvenient and costly, which was the
basic
motivation to consider development of a small-signal or AC analysis
mode
providing the capability to simulate directly in the frequency domain.
In
addition to the single device simulator, the circuit simulator of Minimos-NT
has
been equipped with small-signal capabilities.
After the integration of new assembly and solver modules, which are
also capable of
handling complex-valued linear equation systems, Minimos-NT was extended by
several features for small-signal simulations: for example, calculation
of the
admittance and scattering matrices and the efficient extraction of
various
small-signal parameters (Y-, Z-, S- and H-parameters) or related
figures of
merit (cut-off frequency, maximum oscillating frequency, etc.). In
order to take parasitics introduced by the
measurement setup into account, single devices can be embedded in a
standard
two-port circuit, which allows the extrinsic
parameters to be extracted easily.
The in-house solver module provides two nonstationary iterative
methods,
Bi-CGStab and GMRES(m), in combination with an incomplete factorization
preconditioner. To also meet future requirements, two external solver
modules
have been evaluated and plugged into the solver module. A further
speed-up of
the simulators is highly appreciated, especially for three-dimensional
process
or device simulations, e.g., for the FinFET structure cut-out shown in
the figure. The
simulators are now able to employ the parallel direct solver Pardiso as
well as
four solvers from the Algebraic Multigrid Methods for Systems package.
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