A New Surface Potential-Based Analytical Model for MFIS NCFETs

Abstract

In this article, we present an analytical model for the surface potential ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\psi _{s}$ </tex-math></inline-formula> ) for metal–ferroelectric–insulator–semiconductor (MFIS) negative capacitance field-effect transistors (NCFETs) as a function of the gate voltage, by first developing the models regionwise (weak and strong inversion) and then merging them together in the moderate-inversion region by using a smoothing function. This model for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\psi _{s}$ </tex-math></inline-formula> is used subsequently to obtain the charge and capacitance behavior and eventually to the development of the current–voltage model. It considers various important technology parameters, i.e., substrate doping, ferroelectric (FE) and oxide thicknesses, remnant polarization, and coercive field. All the model results showed an excellent match with those obtained from TCAD simulations. It has also been observed that capacitance matching, and thus, gate control, improves with an increase in the FE thickness and the ratio of the coercive field to remnant polarization, which can be utilized effectively in device and circuit designs for low-power applications. The small-signal parameters, extracted from the current–voltage characteristics, show the first-order continuity, thus making the model suitable for circuit simulation.