The Reliability Impact of Bi Doping on the HfO₂ Charge-Trapping Layer: A First-Principles Study

Hafnia has emerged as a promising material for charge-trapping memory. However, enhancing its trapping performance remains a significant research challenge. In this work, we investigate the influence of Bi impurities on the reliability of HfO₂-based charge-trapping memory devices using first-principles calculations. By examining the impact of Bi impurities on the formation of oxygen vacancies (V_O), we obtained the lowest-energy Bi-V_O3 defect model. Through an exploration of the microstructure, electronic structure, and Bader charge distribution of the Bi-V_O3 defect system, we compare its device performance with the Al-V_O3 defect system. Our findings demonstrate that the Bi-V_O3 defect system exhibits superior electronic retention ability compared to the Al-V_O3 defect system. This suggests that introducing Bi impurities into HfO₂ can enhance the reliability of memory devices and presents a promising dopant solution for improving memory performance.