Full Three-Dimensional Quantum Transport Simulation of Atomistic Interface Roughness in Silicon Nanowire FETs

The influence of interface roughness scattering (IRS) on the performances of silicon nanowire (NW) field-effect transistors is numerically investigated using a full 3-D quantum transport simulator based on an atomistic sp(3)d(5)s* tight-binding model. An interface between silicon and silicon dioxide layers is generated in a real-space atomistic representation using an experimentally derived autocovariance function. An oxide layer is modeled in a virtual crystal approximation using fictitious SiO2 atoms. < 110 >-oriented NWs with different diameters and randomly generated surface configurations are studied. An experimentally observed ON-current and threshold voltage are quantitatively captured by the simulation model. The mobility reduction due to IRS is studied through a qualitative comparison of the simulation results with the experimental data.