The impact of fin-thickness nonuniformities
on carrier transport in FinFETs is analyzed with
a quasi-ballistic transport model based on the multisubband
Monte Carlo technique. Silicon channels
featuring thickness constrictions or enlargements
show subband energy variations due to the changes
in vertical quantization along the fin. We found
that the impact on the on-current is larger when
the nonuniformities are located close to the virtual
source of the device. Furthermore, the sensitivity
of on-current to thickness nonuniformity is essentially
the same when considering different crystal
orientations. Comparison with drift-diffusion simulations
reveals quantitative and qualitative differences
in the predicted drain current trends of these
nanoscale, quasi-ballistic MOS devices.
