With the advent of the fourth industrial revolution, artificial intelligence based on big data is rapidly improved by leaps and bounds. Despite these advances, the hardware for implementing AI has a conventional von-Neumann architecture in which memory and processing units are physically separated, resulting in many inefficiencies in the movement of the data. Neuromorphic computing can overcome the limitations of von-Neumann architecture by storing and computing data simultaneously, such as human synapses, to benefit efficient big data processing. Therefore, resistance-switching devices that can mimic human synapses hardware-wise are actively investigated. However, a conventional resistance-switching device called memristor has suffered from stochastic conductive filament formation, which provokes resistance-switching, hindering its commercialization. In this study, a highly reliable memristor was fabricated through structural improvement by inserting porous structures and a buffer layer using amorphous material compatible with CMOS technologies. In addition, the role of the pore and buffer layer was experimentally demonstrated to identify the resistive-switching mechanism of the device.