US Patent 7939817 Integrated circuit including memory element with spatially stable material

An integrated circuit includes a heater element serving as a first electrode, a second electrode, a memory element comprising resistance changing material coupled to the heater element and to the second electrode, and a diffusion compensation region coupled to the heater element and to the resistance changing material. The diffusion compensation region includes a surplus of at least one diffusible species present in the memory element and provides at least one diffusible species to the memory element.