Utilization of oxygen content modulated Ru electrode to examine the interfacial redox chemistry of ferroelectric Hf_0.5Zr_0.5O₂

The impact of oxygen content in the Ru electrode, grown using atomic layer deposition on ferroelectricity in Hf_0.5Zr_0.5O₂ film is investigated. The oxygen content in Ru can be modulated by simply adjusting the deposition temperature from 210 °C to 300 °C. Higher oxygen content in Ru reduces the oxygen vacancy concentration in subsequently grown Hf_0.5Zr_0.5O₂ film, thereby mitigating the wake-up effect. However, the monoclinic phase fraction increased with decreasing Ru deposition temperature, resulting in a decrease in remanent polarization. The decreased oxygen vacancy concentration by oxygen diffusion from Ru electrode deposited at 210 °C could decrease the leakage current density compared to that grown at higher temperatures. Nonetheless, the switching endurance of Hf_0.5Zr_0.5O₂ film grown on Ru deposited at 210 °C was shorter than those on Ru deposited at 300 °C by 2 order of magnitude, being attributed to the oxygen diffusion caused interfacial damages. This observation suggests that the interfacial redox reactions between the electrode and Hf_0.5Zr_0.5O₂ critically influence defect concentration, polymorphism, and the resulting ferroelectricity when using an atomic layer deposited Ru electrode to examine the impact of interfacial redox chemistry.