Modeling of ferroelectric field-effect transistors and their application in non-volatile SRAM

Abstract

Ferroelectric Field-Effect Transistors (FeFETs) are gaining attention as promising solutions for non-volatile memory applications due to their fast-switching speed, low power operation, and inherent capability for non-destructive readout. Despite recent advancements, accurate device-level modeling remains critical for evaluating their performance in circuit-level applications. This thesis was focused on the modeling and simulation of FeFETs in the Cadence Virtuoso environment. A standalone ferroelectric capacitor (FeCap) model was developed using the Landau–Khalatnikov equation to capture polarization switching dynamics. Although this FeCap model was not integrated into a FeFET structure, it was created to understand the standalone switching behavior prior to future integration. A previously validated FeFET model from existing literature was employed to simulate a hybrid Static Random Access Memory (SRAM) cell, combining n-type FeFET pull-down transistors with conventional PMOS devices. The study explored the effect of varying ferroelectric thickness on the bistability and retention characteristics of the SRAM. Through dynamic waveform simulations, a critical thickness threshold was identified, beyond which the FeFET exhibits stable non-volatile switching. This work provides insight into the importance of ferroelectric thickness for memory functionality and offers a simulation-based methodology for future FeFET-based circuit design.