Geometric effects in the measurement of the remanent ferroelectric polarization at the nanoscale.

This article focuses on the influence of geometric factors on the measurement of remanent ferroelectric polarization (2Pr) in tungsten/Hf0.5Zr0.5O2/tungsten (W/HZO/W) thin film capacitors, which are relevant for memory and logic device applications. The study compares two capacitor geometries—continuous ferroelectric layers with island top electrodes and fully etched island capacitors—and finds that apparent increases in 2Pr at smaller capacitor sizes in continuous structures arise from processing artifacts, such as ion milling-induced electrode "footing," and fringe electric fields extending beyond the nominal capacitor area. After correcting for these effects using transmission electron microscopy and electric field simulations, the remanent polarization remains constant (~32 μC/cm²) down to 400 nm diameter capacitors. The findings highlight the necessity of precise geometric characterization and consideration of local electric fields to accurately assess intrinsic ferroelectric properties at the nanoscale.