Enhancing the Switching Ratio of HZO FTJs by Co-Optimizing Work Function and Defect Density

HfO2-based ferroelectric tunnel junctions (FTJs) hold great promise but are often limited by a modest switching ratio. Here, we propose a co-optimization strategy that simultaneously tunes the electrode work function and defect density to enhance the tunneling electroresistance (TER) ratio. Using a self-consistent simulator that capture the dynamics of polarization switching and trap occupation, and employing defect parameters calibrated from experiments, we systematically analyze the contribution of trap-assisted current and the impact of electrode work functions and defect density on the TER ratio. Tuning the electrode work function alone yields only a 2× improvement, whereas co-optimizing the electrode work functions and defect density enhances the TER ratio by more than 30×. This co-optimization strategy can be extended to FTJ structures involving dielectric or semiconductor layers, further advancing their potential applications in nonvolatile memory (NVM) and neuromorphic systems.