Enhanced reliability of Hf0.5Zr0.5O2 ferroelectric memory through WOx buffer layer to minimize oxygen vacancies

Abstract

Ferroelectric memory presents numerous advantages, including rapid read/write speeds, high-temperature resistance, and resilience to radiation. However, defects such as oxygen vacancies can undermine its stability and durability. In this study, we have developed a ferroelectric capacitor consisting of Si/W/WOx/Hf0.5Zr0.5O2 (HZO)/WOx/W. The incorporation of two WOx interfacial layers has significantly reduced the concentration of oxygen vacancies at the interface of the HZO film, leading to an impressive decrease in leakage current density by 94.9% compared to the conventional Si/W/HZO/W capacitor. Consequently, the remnant polarization of the capacitor retains 98.9% and 96.3% of its initial value after more than 1011 read/write cycles at voltages of 1.5 V under temperatures of 25 and 150 °C, respectively. Furthermore, during the “1/0” hold process at 150 °C, the imprint voltage is reduced by 44.4% relative to that observed in the Si/W/WOx/HZO/W capacitor. This work significantly enhances the reliability of ferroelectric memory during both read/write operations and retention periods.