First Demonstration of Hafnia-based Selector-Free FeRAM with High Disturb Immunity through Design Technology Co-Optimization

In this work, 3D-stackable hafnia-based selector-free FeRAM is experimentally demonstrated for the first time, showing significantly improved disturb immunity through design technology co-optimization. With ferroelectric (FE) dynamics considered, based on the proposed pulse-disturb analysis method for FE capacitors, the disturb behavior of FE-based cross-point arrays has been systematically and quantitatively investigated. By grain uniformity and interfacial layer optimization, the fabricated optimized Hf0.5Zr0.5O2 (HZO) FE capacitor shows the record best disturb immunity among FE-HZO and 71.3% of MW improvement for FeRAM operation due to the large grain size (>30nm), along with the advantages of enhanced remnant polarization (Pr) (~23 μC/cm
²
), low operation voltage (2.4V), high endurance (10
¹³
cycles), long retention (10 years) and excellent 3D-stackable potential. Moreover, to address the multiple pulses disturb issue, a new disturb-recovery pulsing method is further proposed, showing multi-disturb-free operation for practical cross-point array applications. Based on the above strategies, the first 1 kbit cross-point array for selector-free FeRAM based on the optimized HZO devices is experimentally demonstrated with successful read/write operation, indicating its great potential for high-density and low-power memory applications.