US Patent 7906368 Phase change memory with tapered heater

An embodiment of the present invention includes a method of forming a nonvolatile phase change memory (PCM) cell. This method includes forming at least one bottom electrode; forming at least one phase change material layer on at least a portion of an upper surface of the bottom electrode; forming at least one heater layer on at least a portion of an upper surface of the phase change material layer; and shaping the heater layer into a tapered shape, such that an upper surface of the heater layer has a cross-sectional width that is longer than a cross-sectional width of a bottom surface of the heater layer contacting the phase change material layer.