In recent years, in order to develop brain-like systems, researchers in the world succeeded in mimicking functions of neurons and synapses, basic components of the brain. But the adopted functional materials for artificial synapses are often not able to provide a stable and fast change, which is required in future’s real-time cognitive and image processing. In this work, in order to greatly improve the thermal stability of chalcogenide-based synapses, N-O co-doped fast-speed Sb 2 Te 3 chalcogenide materials fabricated by reactive sputtering are systematically investigated using X-ray diffraction and sheet resistance measurements.