Recoverable ultrathin Hf0.5Zr0.5O2-based ferroelectric tunnel junction

Abstract

Here, we report a ferroelectric tunnel junction (FTJ) based on ultrathin Hf0.5Zr0.5O2 (HZO) that can be electrically recovered from memory fatigue to reach significantly prolongated endurance. A high remanent polarization (Pr) of 19 μC/cm2 is obtained in 3 nm-thick HZO ferroelectric films, and its robust ferroelectricity can be recovered by employing a unipolar negative voltage recovery pulse technique, leading to significantly-prolongated endurance up to 3.7 × 109 cycles and 4.53 × 1010 cycles under bipolar square-waveform field cycling at 105 and 106 Hz, respectively. The fabricated W/WOx/HZO/Pt FTJs exhibited giant tunnel electroresistance ratios of up to 5.8 × 105, attributable to the superb HZO ferroelectrics and the incorporation of sputtered highly conductive WOx interfacial layer. By implementing a similar single-pulse recovery to release the pinned oxygen vacancy defects from the interfaces, the FTJs delivered superior cycling endurance of 108 cycles with a large memory window over 13 000 under 10 ns single-pulse programming, demonstrating the great potential of ultrathin HZO based FTJs as a promising nonvolatile memory. This work would foresee a bright future and pave the way for the practical applications of ultrathin HZO-based FTJ memory.