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 <tex-math notation="LaTeX">$/$ </tex-math> cm) of ~ <tex-math notation="LaTeX">30 ~μ C/ </tex-math> cm 2 with small variation ( <tex-math notation="LaTeX">Δ 2Pᵣ ≤ 2 ~μ C/ </tex-math> cm 2 ; <tex-math notation="LaTeX">Δ 2Pᵣ / 2Pr,pristine ≤9 </tex-math> %) 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.