Synergistic Modulation of Polarization and Leakage Current in MPB-HZO Capacitors via TiO2 Interlayer

Abstract

To address critical reliability concerns in ferroelectric devices, the role of a TiO₂ interlayer in modulating the electrical characteristics of Hf_xZr_1-xO₂ (HZO)-based metal-ferroelectric-metal (MFM) capacitors near the morphotropic phase boundary (MPB) is investigated. The TiO₂ interlayer is inserted at the HZO interface to selectively modulate defect behavior while preserving the desired MPB phase composition. Electrical, structural, and spectroscopic analyses reveal that TiO₂ integration enables 1) suppression of leakage pathways, 2) stabilization of polarization with enhanced dielectric response, 3) modulation of oxygen vacancy (V_O) distribution, and 4) reduction of low-frequency noise (LFN) amplitude. These synergistic effects collectively improve the reliability and energy efficiency of MPB-HZO capacitors, offering a promising interface-engineering strategy for next-generation ferroelectric DRAM technologies.