  The effect of decreasing Drain-Induced Barrier Lowering (DIBL) is one of the
non-desirable short-channel effects in the MOSFETs family, which causes the
threshold voltage of the transistor to be reduced by increasing the voltage of
the drain. This effect makes it impossible for circuit designers to consider VT
as a constant value, and hence, it is necessary to calculate VT as a function
of the drain voltage. Therefore, to consider the effect of DIBL in the design
of integrated circuits, a large computational burden is imposed on the system,
which slows down the simulation process in circuit-level simulators,
particularly when a large number of transistors are to be simulated.
Accordingly, in this paper, a multiple input single output (MISO) Nonlinear
Autoregressive (N-AR) model using the Gram-Schmidt orthogonalization approach
is proposed, that calculates the threshold voltage of the new generation of
MOSFETs, i.e., Junctionless Double-Gate MOSFETs (JL-DG-MOSFETs), with a high
precision and a significant speed-up in the computational procedure of the
model. It is shown that, on average, the proposed numerical method is 313 times
faster than the state-of-the-art analytical model. The calculated percentage of
normalized mean square error between the proposed model and analytical one is
0.435% on average, showing that the proposed approach can be a fast and
accurate candidate for replacing the analytical modeling.
