  Particle-based ensemble semi-classical Monte Carlo (MC) methods employ
quantum corrections (QCs) to address quantum confinement and degenerate carrier
populations to model tomorrow's ultra-scaled MOSFETs. Here we present new
approaches to quantum confinement and carrier degeneracy effects in a
three-dimensional (3D) MC device simulator, and illustrate their significance
through simulation of n-channel Si and III-V FinFETs. Original contributions
include our treatment of far-from-equilibrium degenerate statistics and
QC-based modeling of surface-roughness scattering, as well as considering
quantum-confined phonon and impurity scattering in 3D. Typical MC simulations
approximate degenerate carrier populations as Fermi distributions to model the
Pauli-blocking (PB) of scattering to occupied final states. To allow for
increasingly far-from-equilibrium non-Fermi carrier distributions in
ultra-scaled devices, we instead generate the final-state occupation
probabilities used for PB by sampling the local carrier populations as a
function of energy and energy valley. This process is aided by the use of
fractional carriers or sub-carriers, which minimizes classical carrier-carrier
scattering. Quantum confinement effects are addressed through
quantum-correction potentials (QCPs) generated from Schr\"{o}dinger-Poisson
solvers, as commonly done. However, we use our valley- and
orientation-dependent QCPs not just to redistribute carriers in real space, or
even among energy valleys, but also to calculate confinement-dependent phonon,
impurity, and surface-roughness scattering rates. FinFET simulations are used
to illustrate how, collectively, these quantum effects can substantially reduce
and even eliminate otherwise expected benefits of
In$_{\text{0.53}}$Ga$_{\text{0.47}}$As FinFETs over otherwise identical Si
FinFETs, despite higher thermal velocities in
In$_{\text{0.53}}$Ga$_{\text{0.47}}$As.
