Design of Si0.45Ge0.55-based core–shell-type dual-material dual-gate nanotube TFET with source pocket technique

In this paper, dual-material dual-gate nanotube TFET (DMDG-NTTFET) is proposed. Dual gates in this regard are of the core–shell type, and dual-gate materials (GM1 and GM2) are used as control gate having work functions of $${\varphi }_{tunnel}$$ and $${\varphi }_{Auxiliary}$$ , respectively. The device is further explored with source pocket and various underlap gate lengths. When device characteristics are compared with the conventional NWTFET, significant improvements in ION, IOFF, ION/IOFF, transconductance (gm), recombination rate, and transconductance factor (gm/Id) are observed. The proposed structure also results in improved linearity and tunnelling in the device. The effects of the device variables, such as $${\varphi }_{tunnel}$$ , $${\varphi }_{Auxiliary}$$ , source pocket length (L1), gate underlap length (L2), and molar concentration in Si1-xGex (x), on various analog performance indicators, such as transconductance factor (gm/Id), transconductance (gm), unity gain cut-off frequency (fT), intrinsic device delay ( $$\tau $$ ), transconductance frequency product ( $$\left({g}_{m}/{I}_{d}\right)*{f}_{T}$$ ), and gain–bandwidth product (GBWP), have been investigated. The ION and ION/IOFF in source pocket dual-material dual-gate nanotube TFET (SPDMDG NTTFET) is improved by a factor of 21.11 and 846.12, respectively. The subthreshold slope achieved using the proposed structure is 18.28 mV/decade.