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.