Ultrafast Negative Capacitance Transition for 2D Ferroelectric MoS2/Graphene Transistor

Abstract

AbstractNegative capacitance gives rise to subthreshold swing (SS) below the fundamental limit by efficient modulation of surface potential in transistors. While negative‐capacitance transition is reported in polycrystalline Pb(Zr0.2Ti0.8)O3 (PZT) and HfZrO2 (HZO) thin‐films in few microseconds timescale, low SS is not persistent over a wide range of drain current when used instead of conventional dielectrics. In this work, the clear nano‐second negative transition states in 2D single‐crystal CuInP2S6 (CIPS) flakes have been demonstrated by an alternative fast‐transient measurement technique. Further, integrating this ultrafast NC transition with the localized density of states of Dirac contacts and controlled charge transfer in the CIPS/channel (MoS2/graphene) a state‐of‐the‐art device architecture, negative capacitance Dirac source drain field effect transistor (FET) is introduced. This yields an ultralow SS of 4.8 mV dec−1 with an average sub‐10 SS across five decades with on‐off ratio exceeding 107, by simultaneous improvement of transport and body factors in monolayer MoS2‐based FET, outperforming all previous reports. This approach could pave the way to achieve ultralow‐SS FETs for future high‐speed and low‐power electronics.