ZrO2-HfO2 Superlattice Ferroelectric Capacitors With Optimized Annealing to Achieve Extremely High Polarization Stability

The ferroelectric polarization stability and dielectric characteristics of ZrO ₂ -HfO ₂ superlattice (SL) ferroelectric layer Metal-Ferroelectric-Metal (MFM) capacitor fabricated with various post-metal annealing (PMA) temperatures were presented. It was demonstrated that ZrO ₂ -HfO ₂ SL MFM capacitors with increased post metallization PMA temperature (i.e., 600 °C) showed improved polarization stability with almost wake-up free and polarization fatigue free characteristics. In this work, we have shown that highly stable remanent polarization (2P _r @ 3MV $/$ cm) of ~ $30 ~\mu \text{C}/$ cm ² with small variation ( $\Delta 2\text{P}_{r} \le 2 ~\mu \text{C}/$ cm ² ; $\Delta 2\text{P}_{r} / 2\text{P}_{r,pristine} \le9$ %) up to 10 ¹¹ cycles of field cycling were exhibited by the atomic layer deposition (ALD) deposited ZrO ₂ -HfO ₂ superlattice with 600 °C PMA. To our knowledge, the nearly “ wake-up”-free and fatigue-free polarization behavior up to 10 ¹¹ cycles are among the best polarization stability for the hafnium zirconium oxide based MFM capacitors sustained endurance tests for more than 10 ¹⁰ cycles.