Temperature-dependent Defect Behaviors in Ferroelectric Hf0.5Zr0.5O2 Thin Film: Re-wakeup Phenomenon and Underlying Mechanisms

Aiming at deep insights into the defect behaviors in the ferroelectric HZO thin film, we present a systematical study on the reliability property of $7\mathrm{~nm}$ HZO capacitor at the high-temperature range $(300\sim 420\mathrm{~K})$. For the first time, the rewakeup phenomenon is observed with cycling operation at high temperatures. By characterization on the switching time, fatigue rate, and leakage currents, the underlying defect-related mechanisms are discussed. It is considered that defects at grain boundaries could be an important reason because the trapped positive charge will induce the dipole pinning during the fatigue stage, but stronger electron injection (higher leakage) can release this pinning and cause the re-wakeup phenomenon. Our results strongly indicate that grain boundary engineering could be the key to ultra-thin HZO optimizations.