Impact of interface traps and fixed interface charges on polarization and TER ratio in MFIS ferroelectric tunnel junctions: A TCAD study

Abstract

Hafnium dioxide (HfO2)-based ferroelectric tunnel junctions (FTJs) have the potential to dominate the next generation non-volatile memories and neuromorphic computing applications. These devices have been found to be promising memory devices due to their non-destructive readout, CMOS compatibility, and cost-effectiveness. However, the presence of charge trapping/de-trapping and fixed charges can be challenging for read/write operations as they can alter the polarization and cause device variability. This work primarily focuses on the impact of interface traps and fixed charges on the performance of metal–ferroelectric–insulator–semiconductor-based FTJs using technology computer-aided design simulations. This study comprises donor- and acceptor-type traps at the interface of silicon/silicon dioxide (Si/SiO2) and fixed charges (positive and negative) at the SiO2/HfO2 interface. As indicated by the simulation results, the interface states impact the depolarization field (Ed) and remanent polarization (Pr). This eventually affects the read current density (J) and varies the tunneling electroresistance (TER) ratio of the FTJ devices. A comprehensive analysis of the individual and combined effects of interface traps and fixed interface charges highlights their critical role in determining key FTJ performance metrics.