Patent ID: 8426967
Filing Date: 2013-04-23
Classification: H01L

Abstract:
1. A semiconductor structure configurable for use as a nonvolatile storage element, the semiconductor structure comprising: a first electrode; an insulating layer formed on at least a portion of an upper surface of the first electrode; a pillar traversing the insulating layer and being recessed relative to an upper surface of the insulating layer, the pillar comprising a heater formed on at least a portion of the upper surface of the first electrode, and a collar formed on sidewalls of the insulating layer proximate the heater and on at least a portion of an upper surface of the heater, a lower surface of the collar being formed entirely on the at least a portion of the upper surface of the heater, wherein the heater is formed of carbon or titanium nitride or tantalum nitride, and wherein the beater has a width that is less than a width of the first electrode; as phase change material layer formed on at least a portion of the upper surface of the insulating layer and tilling a volume defined by the upper surface of the heater and an upper surface of the collar, at least a portion of the phase change material being in physical contact with the carbon or titanium nitride or tantalum nitride material forming the upper surface of the heater; and at least a second electrode formed on at least a portion of an upper surface of the phase change material layer, wherein the collar is configured so as to concentrate a flow of current from the phase change material layer formed on the upper surface of the insulating layer to within the phase change material filling said defined volume and cause a state transition of substantially all of the phase change material filling said defined volume due to localized heating, when a switching current signal is applied between the first and second electrodes.