(Invited) 2D NC-FET, FE-FET and FeS-FET

Abstract

The so-called Boltzmann Tyranny defines the fundamental thermionic limit of the subthreshold slope (SS) of a metal-oxide-semiconductor field-effect transistor (MOSFET) at 60 mV/dec at room temperature and, therefore, precludes the lowering of the supply voltage and the overall power consumption. Adding a ferroelectric dielectric as a negative capacitor to the gate stack of a MOSFET may offer a promising solution to bypassing this fundamental barrier. Meanwhile, two-dimensional (2D) semiconductors, such as atomically thin transition metal dichalcogenides (TMDs) due to their low dielectric constant, and ease of integration in a junctionless transistor topology, offer enhanced electrostatic control of the channel. In this talk, we will review the recent progress on negative capacitance field-effect transistors (NC-FET) and ferroelectric field-effect transistors (Fe-FET) using TMDs as the transistor channels. [1,2] More importantly, a new device concept, which we call as ferroelectric semiconductor field-effect transistor (FeS-FET), was proposed and experimentally demonstrated. [3] In this novel FeS-FET, a 2D ferroelectric semiconductor α-In2Se3 is used to replace conventional semiconductor as channel. α-In2Se3 is identified due to its proper bandgap, room temperature ferroelectricity, the ability to maintain ferroelectricity down to a few atomic layers and the feasibility for large-area growth.[1] M. Si et al. Nature Nanotechnology 13, 24-28 (2018).[2] M. Si et al. 2017 IEDM, pp. 573-576 (2017).[3] M. Si et al. Nature Electronics 2, in press (2019).