Ferroelectric-like Behavior Originating from Oxygen Vacancy Dipoles in Amorphous Film for Non-volatile Memory

Traditional ferroelectric devices suffer a lack of scalability. Doped HfO₂ thin film is promising to solve the scaling problem but challenged by high leakage current and uniformity concern by the polycrystalline nature. Stable ferroelectric-like behavior is firstly demonstrated in a 3.6-nm-thick amorphous Al₂O₃ film. The amorphous Al₂O₃ devices are highly scalable, which enable multi-gate non-volatile field-effect transistor (NVFET) with nanometer-scale fin pitch. It also possesses the advantages of low process temperature, high frequency (~GHz), wide memory window, and long endurance, suggesting great potential in VLSI systems. The switchable polarization (P) induced by the voltage-modulated oxygen vacancy dipoles is proposed.