Stoichiometry- and lattice-tunable MoNx as a novel electrode platform for ferroelectric Hf0.5Zr0.5O2 capacitors

Ferroelectricity in (Hf,Zr)O2 thin films is highly sensitive to bottom-electrode chemistry, as interfacial redox reactions during atomic layer deposition (ALD) and subsequent annealing can generate defective interlayers and alter oxygen-vacancy distributions. Here, we propose a stoichiometry- and lattice-tunable molybdenum nitride (MoNx) electrode platform that enables single-layer interfacial engineering through control of the Mo:N ratio. MoNx films with x = 0.00, 0.05, 0.52, and 0.79 (denoted as Mo, 05MoN, 52MoN, and 79MoN) were sputter-deposited and integrated into symmetric MoNx/Hf0.5Zr0.5O2/MoNx capacitors containing 8 nm-thick ALD Hf0.5Zr0.5O2. Structural analysis confirms a transition from Mo (110)-textured films to rock-salt-type MoNx with a (111) texture at higher N contents, while electrode-grade resistivity is maintained (≤ 200 μΩ∙cm for 52MoN). Chemical analyses reveal that increasing the N content substantially suppresses ALD-induced electrode oxidation and reduce the thickness of the oxidized interfacial-layer by 47.7% for 52MoN relative to Mo; N incorporation into the Hf0.5Zr0.5O2 (HZO) near the bottom interface is also detected. Consistently, the monoclinic phase fraction decreases from ~ 21% for Mo to < 5% for 52MoN and 79MoN. All capacitors exhibit minimal wake-up, with a ≤ 3.0% change in double remanent polarization after 104 cycles at 3 MV∙cm-1. Benchmarking against other stoichiometry-controlled electrode systems (e.g., TaNx, RuOx, and TiNx) shows that the MoNx platform maintains high pristine polarization (> 47.5 μC∙cm-2) while suppressing wake-up across a wide compositional range. Endurance improves markedly with N content, reaching ~ 108-109 cycles for high-N MoNx electrodes, depending on the cycling voltage. These results establish MoNx as a scalable, composition-engineerable electrode system that couples interfacial microstructure control with enhanced ferroelectric reliability in HZO thin films.