Atomistic treatment of interface roughness in Si nanowire transistors with different channel orientations

摘要

Nanowire transistors with a perfect crystal structure and a well-defined Si-SiO_2 interface cannot be grown with the actual technology. The shape of the semiconducting channel varies from source to drain. By self-consistently coupling the three-dimensional Schrodinger and Poisson equations, interface roughness (IR) effects are studied in Si triple-gate nanowire transistors with [100], [110], [111], and [112] oriented channels. The full-band electronic transport is computed in the nearest-neighbor sp~3d~5s~* tight-binding model. IR is included by adding or removing atoms at the Si surface. A comparison of the different channel orientations is achieved by calculating the variations of the transistor threshold voltage.