A porous memory device, such as a memory or a switch, may provide a top and bottom electrodes with a memory material layer (e.g. SiOx) positioned between the electrodes. The memory material layer may provide a nanoporous structure. In some embodiments, the nanoporous structure may be formed electrochemically, such as from anodic etching. Electroformation of a filament through the memory material layer may occur internally through the layer rather than at an edge at extremely low electro-forming voltages. The porous memory device may also provide multi-bit storage, high on-off ratios, long high-temperature lifetime, excellent cycling endurance, fast switching, and lower power consumption.