Impact of Physical and Material Parameters on the Threshold Voltage and the Channel Resistance of Nanowire Field-Effect Transistors for Advanced Nanoscale Devices

Abstract

This work studies the impact of different physical and material parameters on the channel resistance, Rch, and threshold voltage, Vth, of nanowire field-effect transistors (NWFETs). In particular, by means of detailed numerical simulations, we investigate the role of the channel length, nanowire diameter, gate oxide thickness, channel-doping concentration, energy bandgap, oxide thickness, and gate oxide permittivity in a wide range of temperatures (200–500 K). Our findings show that optimal values for both Rch and Vth are achieved by reducing the nanowire channel length, as well as by increasing the nanowire diameter and doping concentration. Furthermore, NWFETs benefit from using wide-bandgap materials and thinner oxide layers with a higher permittivity. Notably, in short-channel NWFETs operating under ballistic transport, channel resistance remains nearly constant with temperature, governed by quantum conductance and injection statistics rather than temperature-sensitive scattering. These results underscore the complex interplay between material selection, doping levels, and device geometry in shaping the threshold voltage and the channel resistance of NWFETs. Also, they are useful for enhancing the device stability and advancing the design of NWFETs for the next-generation of nanoscale transistors.