Patent ID: 8525144

Claim:
A method of forming a device, the method comprising the steps of: forming a first dielectric layer on a substrate; depositing a layer of heater material on the first dielectric layer; patterning the layer of heater material to form a heater on the first dielectric layer; after patterning the layer of heater material to form the heater, forming a second dielectric layer overlaying the heater and the first dielectric layer, wherein the second dielectric layer is in contact with the heater and portions of the first dielectric layer surrounding the heater; forming an opening in the second dielectric layer down to the heater, the opening having a lower portion and an uppermost portion; forming a phase-change element at least mostly tilling the lower portion of the opening and in thermal contact with the heater, wherein the step of forming the phase-change element comprises depositing a layer of phase-change material onto an upper surface of the second dielectric layer to completely fill the opening formed in the second dielectric layer with phase change material, and polishing the layer of phase-change material to remove the phase-change material from the upper surface of the second dielectric layer and to recess the phase-change material in the opening down below the upper surface of the second dielectric layer; forming a diffusion barrier layer overlying the phase-change element and at least mostly filling the uppermost portion of the opening; wherein at least a fraction of the phase-change element is operative to change between lower and higher electrical resistance states in response to an application of an electrical signal to the heater; and forming a metal line over the opening in contact with the diffusion barrier layer, wherein the diffusion barrier layer is interposed between the phase-change element and the metal line.