Ensemble Monte Carlo simulations of ultra sub-micron metal-oxide-semiconductor-field-effect-transistors

A 50 nm n-Metal-Oxide-Semiconductor-Field-Effect-Transistor (MOSFET) has been studied by Ensemble Monte Carlo (EMC) simulation, including a novel physical model for the treatment of surface roughness and impurity scattering in the Si inversion layer. In particular, this study shows how these scattering mechanisms affect the transport transient response and steady-state regime in a 50 nm gate-length n-MOSFET. Quantum-mechanical effects are also accounted for through the use of a smoothed “effective” potential. A set of I_ds-V_ds curves for the transistor is shown. It is found that the smoothing of the potential to account for quantum effects has a strong impact on the electron transport properties, both in transient and steady-state regimes. Results for the impact that impurity and surface-roughness scattering mechanisms have on the average velocity of the carriers in the channel and the current flowing through the device are also shown. It is found that time-scales as short as 0.1 to 0.2 ps are enough to reach a steady-state channel electron average velocity.; The physical model to treat impurity scattering in the bulk and the surface-roughness scattering in the 2D-silicon inversion layer accounts for a novel approach for the treatment of these scattering mechanisms in a 2D electron gas, without the need to introduce scattering rates among the quantized subbands. The 3D Ensemble Monte Carlo simulated mobility results agree very well with measured silicon bulk and inversion layer mobility.