Deep Sight of Temperature-Dependent Wake-Up Effect of Hf_0.5Zr_0.5O₂ Capacitors and Characterization

Doped HfO₂ ferroelectrics have attracted significant attention owing to their compatibility with CMOS processes in memory applications. The evolution of phases in doped HfO₂ films during the wake-up process remains a subject of ongoing interest. Using precession electron diffraction (PED), this study investigates the phase evolution in Hf_0.5Zr_0.5O₂ (HZO) capacitors at various wake-up temperatures (T_wake). An increasing concentration of the orthorhombic phase (o-phase) is observed to correlate positively with T_wake, leading to enhanced polarization switching (PSW) with a value of 30.5 µC/cm² at elevated T_wake. Following the operation at higher T_wake, transmission electron microscopy (TEM) reveals the formation of large single grains within a 40-nm-long region. The regrowth of o-phase grains results in grain elongation, which reduces the number of grain boundaries (GBs). Leakage current curves of all HZO samples were analyzed and fitted to different conduction mechanisms. Ultimately, elevated T_wake improves the endurance of HZO capacitors, suggesting that fewer grain boundaries can inhibit the formation of conductive filaments and enhance device reliability.