High and low-field contact resistances in trigate devices in a Non-Equilibrium Green's Functions framework

We compute the contact resistances at low drain bias in Trigate and FinFET devices with widths and heights in the 4 to 24 nm range, using a Non-Equilibrium Green's Function approach. Electron-phonon, surface roughness and Coulomb scattering are taken into account. The analysis of the quasi-Fermi level profile reveals that the areas under the spacers are major contributors to the contact resistance at low field, due to the poor electrostatic control over the carrier density under the spacers. The impact of design parameters (cross-section and doping profile) on the contact resistance is analyzed and the simulations are compared to experimental data. At high drain bias, the contributions of phonons and impurities scattering in the source and drain are also computed and discussed.