Computational study of transition metal dichalcogenide cold source MOSFETs with sub-60 mV per decade and negative differential resistance effect

Abstract

To extend the Moore’s law in 5 nm node, a large number of two dimensional (2D) materials and devices have been researched, among which the ‘cold’ metals 2H MS2 (M = Nb, Ta) with unique band structures are expected to achieve the sub-60 mVdec−1 subthreshold swing (SS). We explored the electronic properties and ballistic quantum transport performance of ‘cold’ metals and the corresponding MOSFETs with idealized structures. The studied ‘cold’ metal field-effect transistors (CM-FETs) based on the ‘cold’ metals are capable to fulfill the high-performance (HP) and low-dissipation (LP) goals simultaneously, as required by the International Technology Roadmap for Semiconductors (ITRS). Moreover, gaps of ‘cold’ metals CM-FETs also demonstrate negative differential resistance (NDR) property, allowing us to further extend the use of CM-FETs. Owing to the wide transmission path in the broken gap structure of NbS2/MoS2 heterojunction, the 4110 μAμm−1 peak current, several orders of magnitude higher than the typical tunneling diode, is achieved by NbS2/MoS2 CM-FET. The largest peak-valley ratio (PVR) 1.1×106 is obtained by TaS2/MoS2 CM-FET with VGS = −1 V at room temperature. Our results claim that the superior on-state current, SS, cut-off frequency and NDR effect can be obtained by CM-FETs simultaneously. The study of CM-FETs provides a practicable solution for state-of-the-art logic device in sub 5 nm node for both more Moore roadmap and more than Moore roadmap applications.