Currently, semiconductor devices in production utilize gate lengths as short as 65 nm, with reduction to ca. 20 nm expected in the next 5-7 years. These devices are expected to be dominated by quasi-ballistic, quantum transport in the active region and strongly nonequilibrium relaxation in the drain region. , Understanding has developed through self-consistent simulations as a major tool for predictive behavior of new devices, particularly with kinetic transport handled via a multi-particle Monte Carlo approach. Initial quantum effects have been incorporated into such simulations via an effective potential approach with great success, and we will discuss the application to small fully-depleted silicon-on-insulator devices. As devices grow smaller, however, more advanced techniques, such as the non-equilibrium Green’s functions (NEGF) must be utilized. Here, we discuss the constraints upon these approaches that must be incorporated into NEGF modeling of small devices. Nevertheless, approaches which derive from these NEGF structures, such as the Wigner distribution function, can still be implemented via the kinetic Monte Carlo approaches. The application of this approach to the modeling of a resonant tunneling diode also will be discussed.