Negative Capacitance Field-Effect Transistor Based on a Two-Dimensional Ferroelectric

Negative capacitance field effect transistors (NCFETs) based on ferroelectric materials have been the focus of intensive research activities because of their relatively small sub-threshold swing. This work proposes and presents a comprehensive study of a NCFET based on few-layer $\alpha$-In2 Se3 as the ferroelectric in order to reduce the sub-threshold swing through voltage amplification effect. By employing first principles electronic structure calculations, the Landau constants of mono and few-layer $\alpha$-In2 Se3 are extracted which were utilized for analyzing the characteristics of a NCFET with a monolayer MoS2 as the channel material. Sub-threshold swings in the range of $\sim 27 -59$ mV/dec were achieved for few-layer $\alpha$-In2 Se3 that can be further improved by increasing the thickness of the ferroelectric layer and by using a thinner or high-$\kappa$ insulate layer.