The impact of lead geometry and discrete doping on NWFET operation

This work investigates the influence of discrete dopant positions and lead geometry on the contact resistance in ultrascaled nanowire field effect transistors (NWFET). We use Green´s function approach self-consistently coupled with Poissons equation to show that impurity levels play an important role in current transmission from the highly doped regions to the channel of realistic NWFETs. We find that the best ON-state current is obtained when the impurities are placed in the narrow regions close to channel entrance, and that the closer is the impurities to the Si/SiO2 interfaces the better is the ON-state current. This could be attributed to the dielectric confinement occuring in narrow nanowires. These results show that careful control of both shape and dopant positions is needed to optimize contact resistance and can be of a great interest to NWFET designers to boost the performance of the forthcoming device generations.