Variability Analysis and Improvement Strategies for Nanoscale Ferroelectric Hf₀.₅Zr₀.₅O₂ Utilizing Schottky Emission Current in Switchable Diode

In this work, we proposed a novel variability analysis method in nanoscale ferroelectric (FE) Hf<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{0}.{5}}$ </tex-math></inline-formula>Zr<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{0}.{5}}$ </tex-math></inline-formula>O2 (HZO) using FE diode. The polarization variability was indirectly evaluated from the variation of Schottky emission (SE) current, which is the dominant conduction mechanism in FE diode. Using this method, we investigated two strategies to improve variability: 1) microwave annealing (MWA) and 2) HfO2 interfacial layer (IL) insertion. Low monoclinic (m-) phase fraction with MWA and scaled HZO grain size with HfO2 IL insertion contribute to the improvement of variability. Effectively reduced thermal budget and improved endurance were also achieved. Our proposed method and strategies demonstrate strong potential for applications in scaled FE memory devices.