  In this work we propose a fully experimental method to extract the barrier
lowering in short-channel saturated MOSFETs using the Lundstrom backscattering
transport model in a one sub-band approximation and carrier degeneracy. The
knowledge of the barrier lowering at the operative bias point in the inversion
regime is of fundamental importance in device scaling. At the same time we
obtain also an estimate of the backscattering ratio and of the saturation
inversion charge. Respect to previously reported works on extraction of
transport parameters based on the Lundstrom model, our extraction method is
fully consistent with it, whereas other methods make a number of approximations
in the calculation of the saturation inversion charge which are inconsistent
with the model. The proposed experimental extraction method has been validated
and applied to results from device simulation and measurements on short-channel
poly-Si/SiON gate nMOSFETs with gate length down to 70 nm. Moreover we propose
an extension of the backscattering model to the case of 2D geometries (e.g.
bulk MOSFETs). We found that, in this case, the backscattering is governed by
the carrier transport in a few nanometers close to the silicon/oxide interface
and that the value of the backscattering ratio obtained with a 1D approach can
be significantly different from the real 2D value.
