Utilization of oxygen content modulated Ru electrode to examine the interfacial redox chemistry of ferroelectric Hf0.5Zr0.5O2

The impact of oxygen content in the Ru electrode, grown using atomic layer deposition on ferroelectricity in Hf 0.5 Zr 0.5 O 2 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 0.5 Zr 0.5 O 2 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 0.5 Zr 0.5 O 2 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 0.5 Zr 0.5 O 2 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. • Oxygen contents in atomic layer deposited Ru electrode could be modulated by simply adjusting deposition temperature. • XPS confirmed oxygen diffusion from Ru into Hf 0.5 Zr 0.5 O 2 films, resulting in reduced oxygen vacancy concentration. • XRD showed a decrease in monoclinic phase fraction from 15.4 % to 8.0 % as Ru deposition temperature rose from 210 °C to 300 °C. • Remanent polarization increased from 18.6 μC/cm 2 to 27.1 μC/cm 2 as Ru deposition temperature rose from 210 °C to 300 °C. • Ru deposited at 210 °C suppressed leakage current by 1.5 orders but reduced endurance by 1 order due to interfacial damage.