Improvement in the polarization properties in thin ferroelectric Hf0.5Zr0.5O2 films by two-step flash lamp annealing

In this study, we systematically studied the polarization properties of thin ferroelectric Hf0.5Zr0.5O2 (HZO) films annealed by flash lamp annealing (FLA). We have recently proposed a unique annealing method, two-step FLA, which features high temperature annealing with a minimal increase in thermal budget. Using this technique, we observed improvements in the polarization properties in 5 nm HZO films. These were an increase in the remanent polarization (2Pr) to 24.2 μC cm−2 and better durability compared with other more conventional annealing techniques. In addition, we confirmed that there was no clear degradation in 2Pr under thermal stress. Two-step FLA is one of the effective ways to obtain ferroelectricity with high values of 2Pr and good durability in HZO films thinner than 5 nm.