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The wake-up phenomenon widely exists in hafnia-based ferroelectriccapacitors, which causes device parameter variation over time. Crystallizationat higher temperatures have been reported to be effective in eliminatingwake-up, but high temperature may yield the monoclinic phase or generate highconcentration oxygen vacancies. In this work, a unidirectional annealing methodis proposed for the crystallization of $\mathrm{Hf_{0.5}Zr_{0.5}O_2}$ (HZO)superlattice ferroelectrics, which involves heating from the$\mathrm{Pt/ZrO_2}$ interface side. Nanoscale $\mathrm{ZrO_2}$ is selected toresist the formation of monoclinic phase, and the chemically inert Pt electrodecan avoid the continuous generation of oxygen vacancies during annealing. It isdemonstrated that $\mathrm{600^oC}$ annealing only leads to a moderate contentof monoclinic phase in HZO, and the TiN/HZO/Pt capacitor exhibits wake-up freenature and a $2P_\mathrm{r}$ value of 27.4 $\mu\mathrm{C/cm^2}$. On the otherhand, heating from the $\mathrm{TiN/HfO_2}$ side, or using $\mathrm{500^oC}$annealing temperature, both yield ferroelectric devices that require a wake-upprocess. The special configuration of $\mathrm{Pt/ZrO_2}$ is verified bycomparative studies with several other superlattice structures and HZOsolid-state solutions. It is discovered that heating from the$\mathrm{Pt/HfO_2}$ side at $\mathrm{600^oC}$ leads to high leakage current anda memristor behavior. The mechanisms of ferroelectric phase stabilization andmemristor formation have been discussed. The unidirectional heating method canalso be useful for other hafnia-based ferroelectric devices.

Designing wake-up free ferroelectric capacitors based on the $\mathrm{HfO_2/ZrO_2}$ superlattice structure