Vanadium-Doped Hafnium Oxide: A High-Endurance Ferroelectric Thin Film with Demonstrated Negative Capacitance

Abstract

This study proposes and validates a novel CMOS-compatible ferroelectric thin-film insulator made of vanadium-doped hafnium oxide (V:HfO₂) by using an optimized atomic layer deposition (ALD) process. Comparative electrical performance analysis of metal–ferroelectric–metal capacitors with varying V-doping concentrations, along with advanced material characterizations, confirmed the ferroelectric behavior and reliability of V:HfO₂. With remnant polarization (P_r) values up to 20 μC/cm², a coercive field (E_c) of 1.5 MV/cm, excellent endurance (>10¹¹ cycles without failure, extrapolated to 10¹² cycles), projected 10-year nonvolatile retention (>100 days measured), and large grain sizes of ∼180 nm, V:HfO₂ emerges as a promising robust candidate for nonvolatile memory and neuromorphic applications. Importantly, negative capacitance (NC) effects were observed and analyzed in V:HfO₂ through pulsed measurements, demonstrating its potential for NC applications. Finally, this novel ferroelectric shows potential as a gating insulator for future 3-terminal vanadium dioxide Mott-insulator devices and sensors, achieved through an all-ALD process.