Undoped vertical dual-bilayer TFET with a super-steep sub-threshold swing: proposal and performance comparative analysis

Abstract

In this paper, the undoped vertical dual-bilayer tunnel field effect transistor (UV-DBL-TFET) at a low operating voltage (0.5 V) is introduced, and its DC and RF performance parameters are compared with those of the conventional charge plasma-based symmetrical gate electron–hole bilayer TFET (CP-SG-EHBTFET). The charge plasma technique is used in the proposed device to induce the source/drain and electron–hole dual-bilayer channel dopants. Due to the dopingless architecture of the proposed UV-DBL-TFET, its fabrication is simple and efficient, and it does not require an expensive thermal annealing process. Due to its dopingless architecture, the proposed UV-DBL-TFET is immune against random dopant fluctuations. In the study, the quantum confinement effects in the TCAD simulation have been successfully modelled using the Schrodinger approach and the density gradient model. Compared to the conventional CP-SG-EHBTFET, the proposed UV-DBL-TFET has a dual EHB channel, triggers dual line tunnelling, and doubles the band-to-band tunnelling rate and the ON current. Compared to the I ON of 47.33 μA μm−1 and AVSS of 13.53 of the conventional CP-SG-EHBTFET, the proposed UV-DBL-TFET has almost double the ON current of 93.46 μA μm−1 with a reduced AVSS of 12.3 mV dec−1. The proposed UV-DBL-TFET also gives improved RF/analog performance. Compared to the transconductance (g m) of 0.337 mS, the cut-off frequency (f T) of 65.17 GHz, and the gain-bandwidth-product (GBW) of 16.5 GHz of the conventional CP-SG-EHBTFET, the proposed UV-DBL-TFET has a g m of 0.665 mS, a f T of 129.0 GHz, and an GBW of 32.6 GHz, an almost doubled improvement. Furthermore, the proposed UV-DBL-TFET-based CMOS inverter has also been comprehensively studied, and perfect complementary inverter action has been obtained, suggesting great potential for future low-power applications.