HfO2/TiO2/HfO2 tri-layer high-K gate oxide based MoS2 negative capacitance FET with steep subthreshold swing

Abstract

Two-dimensional (2D) materials have gained huge attention due to their ultimate thinness that can help dominate the short channel effect caused by transistor miniaturization. Molybdenum disulphide (MoS2) is one of the most promising 2D materials that has an extremely thin body, facilitates aggressive scaling, and has a high intrinsic bandgap, which allows it to be utilized fairly for transistor applications. In this work, we report a 2D MoS2 based negative capacitance field effect transistor with a novel HfO2/TiO2/HfO2 tri-layer structure as the high-K gate oxide and lead zirconate titanate, Pb(Zr1-xTix) O3 (PZT), as the ferroelectric in the gate stack. The extensively high Ion/Ioff of 3×1014 (∼six orders higher) and the large transconductance of 1.15 mS/μm (∼25 times higher) are the most spectacular output characteristics of the device, which outperforms all the previous results. The incorporation of a negative capacitance effect exhibits a minimum subthreshold swing of 42.6 mV/dec, which can be realized by introducing 50 nm of a ferroelectric PZT layer over the gate dielectric. Furthermore, a high improvement in the on-state current of ∼177 μA/μm was reported. These results indicate that the proposed device structure provides a new insight into nanoelectronic devices with ultra-low power consumption.