Formation-polarity-dependent improved resistive switching memory performance using IrO _x/GdO _x/WO _x/W structure

The formation-polarity-dependent improved resistive switching memory performance using a new IrO _x/GdO _x/WO _x/W structure has been investigated. The memory device has been observed by both high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. The thicknesses of the GdO _x and WO _x layers are observed to be apprO _ximately 15 and 5.5 nm, respectively. All layers are also analyzed by X-ray photoelectron spectroscopy. The resistive switching mechanism is filament formation/rupture in the high-κ GdO _x layer, which is controlled by the O _xygen ion migration in bilayer GdO _x/WO _x films under negative and positive formation polarities. Excellent uniformity of SET/ RESET voltages, low/high resistance states, and switching cycles have been observed under positive formation polarity owing to the charge trapping/detrapping in the high-κ GdO _x switching layer. The memory device shows a long endurance of >104 times, and extrapolated 10-year data retention at 85 °C. This device shows great potential for future nonvolatile memory (NVM) applications.