Achieving Enhanced Ferroelectricity and Reliability in HZO/ZrO 2 Superlattices With Back-End-of-Line Process

Hafnium -based ferroelectric materials have advanced the development of ferroelectric memory devices owing to their excellent CMOS compatibility and tunable properties. However, hafnium-based ferroelectric capacitors typically require high thermal budgets to achieve strong ferroelectricity, which limits their back-end-of-line (BEOL) compatibility. In this work, we demonstrate that the TiN/Hf0.5Zr0.5O2/ZrO2/W superlattice capacitor can exhibit enhanced ferroelectric performance including a remanent polarization (2Pᵣ) exceeding 48 μC/cm² and endurance over 7×1010cycles. The devices also show improved breakdown resistance, as confirmed by both time-zero dielectric breakdown (TZDB) and time-dependent dielectric breakdown (TDDB) tests. Furthermore, first-principles calculations indicate that the HZO/ZrO2superlattice structure facilitates enhanced ferroelectric properties. This enhancement is attributed to the superlattice-induced interfacial stress, which promotes the formation of the ferroelectric orthorhombic phase during low-temperature annealing. This work proposes a BEOL compatible approach to effectively enhance the performance of hafnium-based ferroelectric memory.