Remote Oxygen Scavenging in MFIS Gate Stack With Laminated HfZrO Film

초록

This work experimentally demonstrates remote oxygen scavenging (OS) effect in metalferroelectric-insulator-semiconductor (MFIS) gate stacks including laminated Hf0.5Zr0.5O2 (HZO) film. Despite a high thermal budget of 800 degrees C, the SiO2 interfacial layer (IL) thickness in the OS sample is suppressed to 0.68 nm via remote OS effect, whereas that of NonOS sample regrows to 1.21 nm. Furthermore, the OS effect stabilizes the orthorhombic phase (o-phase) in the laminated HZO film, yielding an enhanced remanent polarization (Pr) of 20.12 -C/cm(2) compared to 18.61 -C/cm(2) for the NonOS sample. Consequently, switching voltage (V-sw) is reduced by 0.55 V relative to the NonOS counterpart. Although leakage current and breakdown voltage are degraded as a trade-off of the OS effect, endurance (>10(5) cycles) and retention (>10 years) are preserved by leveraging the reduced operating voltage of 6.5 V, versus 7 V for the NonOS sample. These results suggest that the remote OS effect of laminated HZO film is a promising strategy for reducing the operating voltage of ferroelectric NAND (FeNAND) devices fabricated under high thermal budget processes.

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