Interfacial Al 2 O 3 effects on Hf 0.1 Zr 0.9 O 2 and the compact current-partitioning model in ferroelectric tunneling junctions

Abstract

In this work we build a compact model to analyze the experimental total current for ferroelectric tunneling junctions (FTJs) with bandgap engineering. Based on our model, an interfacial layer (IL) design is proposed for Hf 0.1 Zr 0.9 O 2 FTJs to achieve non-volatile characteristics and an excellent on–off ratio (∼100×). With the current partition mechanism, the impacts from the ferroelectric current and the tunneling current are quantitatively analyzed and considered in the design for the film stack. The benefit to the on–off ratio from bandgap engineering can be well explained. We also find that non-volatility can be achieved in Hf 0.1 Zr 0.9 O 2 FTJs. Although Hf 0.1 Zr 0.9 O 2 is typically antiferroelectric, non-zero remanent polarization ( P r ) at 0 V is observed in the polarization–voltage loop of the proposed FTJ. The higher orthorhombic phase induced by the inserted Al 2 O 3 IL is validated by physical analyses. The resulting FTJ exhibits stable room-temperature retention over 10 4 s for non-volatile memory applications.