Thickness-dependent retention–endurance trade-off in scaled Hf0.5Zr0.5O2 ferroelectric capacitor

Abstract

Hafnium zirconium oxide (Hf0.5Zr0.5O2) has emerged as a leading candidate for next-generation ferroelectric memory due to its superior scalability. However, the fundamental trade-offs between thickness scaling, endurance, and retention remain unresolved. Here, we systematically investigate W/Hf0.5Zr0.5O2/TiN capacitors with ferroelectric layer thicknesses from 5 to 10 nm, revealing a critical thickness-dependent performance crossover. While 6 and 8 nm films achieve optimal ferroelectric properties (2Pr up to 41 μC/cm2) and good endurance, they suffer from accelerated retention loss, suggesting that prominent (002) texture may enhance charge injection and time-dependent imprint. In contrast, a 5 nm film demonstrates a superior endurance–retention compromise. We attribute this to its significantly lower remanent polarization, which likely stems from a distinct nanocrystalline/amorphous microstructure, suppressing imprint development. Through quantitative imprint analysis, we establish that wake-up cycling simultaneously improves polarization while degrading retention—a fundamental constraint arising from the coupling between spontaneous polarization and charge injection dynamics. These findings reveal thickness-dependent design rules for achieving reliable scaled ferroelectric memories.