Current-Voltage Model for Negative Capacitance Field-Effect Transistors

Abstract

In this letter, a semi-analytical current-voltage model for a negative capacitance field-effect transistor (NCFET) with a ferroelectric material (i.e., BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) is proposed. Surface potential (ψ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</sub> ) in the channel region is determined first by solving the Landau-Khalatnikov (LK) equation numerically with Poisson's equation. Then, the drain-current is achieved based on the current continuity equation using ψ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</sub> determined earlier. In addition, by introducing a fitting potential for a given drain-voltage,threshold voltage shift can be captured, resulting in accurate surface potential and drain-current at different gate voltages. We have verified our model using the technology computer-aided design (TCAD)-MATLAB simulation, and our model exhibits an excellent agreement to the simulation results. In addition, the impacts of the ferroelectric thickness and channel doping concentration on the device performance and hysteresis window of NCFET are thoroughly explored.