US Patent 7800094 Resistance memory with tungsten compound and manufacturing

Memory devices based on tungsten-oxide memory regions are described, along with methods for manufacturing and methods for programming such devices. The tungsten-oxide memory region can be formed by oxidation of tungsten material using a non-critical mask, or even no mask at all in some embodiments. A memory device described herein includes a bottom electrode and a memory element on the bottom electrode. The memory element comprises at least one tungsten-oxygen compound and is programmable to at least two resistance states. A top electrode comprising a barrier material is on the memory element, the barrier material preventing movement of metal-ions from the top electrode into the memory element.