US Patent 7719039 Phase change memory structures including pillars

A phase change memory cell has a first electrode, a heater, a phase change material, and a second electrode. The heater is over the first electrode, and the heater includes a pillar. The phase change material is around the heater. The second electrode is electrically coupled to the phase change material. In some embodiments, a method includes forming a electrode layer over a substrate, depositing a first layer, providing nanoclusters over the first layer, and etching the first layer. The first layer comprises one of a group consisting of a heater material and a phase change material. The first layer may be etched using the nanocluster defined pattern to form pillars from the first layer.