Back-End of Line Compatible Hf_0.5Zr_0.5O₂/ZrO₂/Hf_0.5 Zr_0.5O₂ Stack Achieving 2P_r of 39.6 C/cm² and Endurance Exceeding 10¹⁰ Cycles Under Low-Voltage Operation

In this letter, the back-end of line (BEOL)compatible Hf0.5Zr0.5O2/ZrO2/Hf0.5Zr0.5O2 stack was designed for enhancing both the ferroelectricity and reliability under low-voltage operation. Compared to the conventional H(0.5)Z(0.5)O(2)(HZO) film, the HZO/ZrO2/HZO stack exhibits superior remnant polarization (2P(r)) of 39.6 mu C/cm(2) and 53.8 mu C/cm(2) under 2 MV/cm and 4 MV/cm, respectively. By integrating ZrO2 middle layer (ML) into HZO films, robust reliability was achieved, including a large breakdown electric field of 2.73 MV/cm in 10-year time-dependent dielectric breakdown (TDDB) lifetime, as well as excellent endurance characteristic with a 2P(r) of 38.04 mu C/cm(2) after 4.34 x 10(9) cycles at 2 MV/cm and no breakdown after 6 x 10(10) fatigue cycles at 1.5 MV/cm. It is believed that ZrO2ML could introduce additional strain at a low annealing temperature below 350 degrees C and improve the proportion of the ferroelectric phase in the HZO/ZrO2/HZO stack. The HZO/ZrO2/HZO stack with low-voltage operation shows the great potential for BEOL-compatible non-volatile memory applications