Impacts of the Shell Doping Profile on the Electrical Characteristics of Junctionless FETs

Abstract

This paper presents the impacts of an advanced shell doping profile (SDP) on the electrical characteristics of a junctionless (JL) FET in terms of OFF-current, subthreshold swing (SS), and ON-current by a numerical simulator. Due to the potential mirroring effect, a special observation stemming from the SDP, the carriers can enter the intrinsic region from the doped surface reducing the series resistance though the junction depth is smaller than 5 nm. The proposed doping profile provides an additional structure parameter for designing a JL FET showing the mitigated short-channel effects, a better SS, and a higher ON/OFF current ratio for sub-20-nm channel length. Compared with traditional devices, a JL FET with the proposed SDP shows a lower OFF-current by decades and less electrical characteristics variation caused by the nanowire diameter variation. The SDP not only reduces the series resistance of a JL FET but also poses a possible solution of avoiding the negative impacts of quantum confinement for advanced technology nodes.