Fabrication and Characterization of Ferroelectric Capacitors with a Symmetric Hybrid TiN/W/HZO/W/TiN Electrode Structure.

In this study, HfZrO (HZO) thin-films were deposited using a Co-plasma atomic layer deposition (CPALD) process that combined both remote plasma and direct plasma, for the development of ferroelectric memory devices. Ferroelectric capacitors with a symmetric hybrid TiN/W/HZO/W/TiN electrode structure, incorporating W electrodes as insertion layers, were fabricated. Rapid thermal annealing (RTA) was subsequently employed to control the crystalline phase of the films. The electrical and structural properties of the capacitors were analyzed based on the RTA temperature, and the presence, thickness, and position of the W insertion electrode layer. Consequently, the capacitor with 5 nm-thick W electrode layers inserted on both the top and bottom sides and annealed at 700 °C exhibited the highest remnant polarization (2P = 61.0 μC/cm). Moreover, the symmetric hybrid electrode capacitors annealed at 500-600 °C also exhibited high 2P values of approximately 50.4 μC/cm, with a leakage current density of approximately 4 × 10 A/cm under an electric field of 2.5 MV/cm. The findings of this study are expected to contribute to the development of electrode structures for improved performance of HZO-based ferroelectric memory devices.