A plasma-based ferroelectric undoped HfOx capacitor is fabricated using plasma-enhanced atomic layer deposition (PE-ALD), and the multilevel characteristics of synaptic behavior are investigated. A gradual ferroelectric phase transition in the material is confirmed by grazing incidence X-ray diffraction (GI-XRD) for different O2 plasma periods. The metal-ferroelectric-metal (MFM) capacitor presents excellent remnant polarization (Pr) up to 13 μC/cm2 and a switching endurance of more than 108 cycles. Superior small potentiation/depression nonlinearity (αp/αd = -0.08/-1.66 for voltage modulation stimulation) for synaptic training and almost symmetry training curve (|αp - αd|) are obtained. High stability under multilevel operation with five consecutive cycles of alternating potentiation and depression is exhibited without significant polarization variation for each training step (pulse).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering