We found that the performance of the optimal ML GeSe and GeTe NCTFETs can increase dramatically and exceed the ITRS demands for both LP and HP logic devices at a lower V dd of 0.55 V. Furthermore, we choose four different ferroelectric dielectrics to construct a prototype negative capacitance TFET (NCTFET) to improve the performance of the logic devices. Moreover, the optimal ML GeSe TFETs still surpass the ITRS demands for the LP logic devices at a V dd of 0.65 V. For the optimal ML GeTe TFETs, the values of I on (HP) are even more extensive than those of the optimal ML GeSe TFETs and exceed the ITRS demands for HP devices until V dd is less than 0.65 V. In this study, we explore the device performance limits of the ML GeSe and GeTe TFETs, when their physical gate length is L g = 10 nm with various doping concentrations and supply voltages by the rigorous ab initio quantum transport simulation. Due to their superior stability and dramatic electronic properties, it is of vital scientific significance to explore the device performance limits of the ML GeSe and GeTe TFETs and NCTFETs. However, the performance limits of ML GeSe and GeTe based new-mechanistic devices are not known. Moreover, ML GeSe and GeTe have moderate band gaps 13,15,18–20 and anisotropic electronic properties, 13,15,21 which are very attractive merits for a competitive channel of TFET with a planar homogeneous p–i–n architecture. In contrast to the instability of BP and low carrier mobility of the transition-metal dichalcogenides (TMDs), 9–12 ML GeSe and GeTe possess both air-stability 13,14 and high carrier mobility, 15–17 which are beneficial for the realization of practical equipment. The syntheses of ML GeSe 7 and ML GeTe 8 by mechanical exfoliation have been demonstrated. ML GeSe and GeTe are emerging semiconductors with puckered honeycomb networks such as black phosphorene (BP). To some extent, the device performance of NCTFET would represent the performance limit of a new-mechanism device. 6 found that double-gate Si TFET having an ultrathin body with a negative capacitance can avoid hysteresis and reduce the SS. 5 found that the gate capacitance of Ge/Si NCTFET is 6–9% higher than that of its TFET counterpart. 4 The combination of the two mechanisms, i.e., NCTFET would give a better device performance than TFET or NCFET. The lowest reported SS is only 3.9 mV dec −1 in the vertical Ge–MoS 2 TFET at room temperature, 3 and the minimum SS is reported for the MoS 2 NCFET with ferroelectric hafnium zirconium oxide (HZO) with the value of 6.07 mV dec −1. Relative to the conventional FET, tunneling FET (TFET) and negative capacitance FET (NCFET) offer two new mechanisms to create a deeper subthreshold slope (SS) than the Boltzmann limit of 60 mV dec −1. Introduction The successful fabrication of sub-10 nm conventional field effect transistors (FETs) based on 2D MoS 2, Si nanowires 1 and carbon nanotubes 2 encourages continuing research including but not limited to conventional FETs with new materials figuring out the ideal device performance limits is a vital guide for the real device fabrication. I on of the optimal ML GeSe and GeTe TFETs fulfills the demands of the International Technology Roadmap for Semiconductors (ITRS 2015 version) for low power (LP) and high performance (HP) devices, at the “6/5” node range, while with the aid of 80 nm and 50 nm thickness of ferroelectric SrBi 2Nb 2O 9, both their NC counterparts extend the fulfillments at the “4/3” node range.
With the ferroelectric dielectric acting as a negative capacitance material, the device performances of both the ML GeSe and GeTe NCTFETs outperform their TFET counterparts, particularly for the on-state current ( I on). We propose archetype tunneling field effect transistors (TFETs) with negative capacitance (NC) and use the rigorous ab initio quantum transport simulation to explore the device performance limits of the TFETs based on monolayer (ML) GeSe and GeTe along with their NC counterparts. Exploring the device performance limits is meaningful for guiding practical device fabrication.