Phase-change memory and fabrication method thereof

Abstract

A phase-change memory is provided. The phase-change memory comprises a substrate. A first electrode is formed on the substrate. A circular or linear phase-change layer is electrically connected to the first electrode. A second electrode formed on the phase-change layer and electrically connected to the phase-change layer, wherein at least one of the first electrode and the second electrode comprises phase-change material.

1 . A phase-change memory element, comprising
 a substrate;   a first electrode formed on the substrate;   a circular or linear phase-change layer electrically connected to the first electrode; and   a second electrode formed on the phase-change layer and electrically connected to the phase-change layer, wherein at least one of the first electrode and the second electrode comprises phase-change material.   
     
     
         2 . The phase-change memory element as claimed in  claim 1 , wherein the phase-change material comprises chalcogenide. 
     
     
         3 . The phase-change memory element as claimed in  claim 1 , wherein the dimension of the circular or linear phase-change layer is less than the resolution limit of photolithography process. 
     
     
         4 . The phase-change memory element as claimed in  claim 1 , wherein the dimensions of phase-change layer from top to bottom are the same and the phase-change layer is essentiality perpendicular to the first electrode and second electrode. 
     
     
         5 . A method for fabricating phase-change memory elements, comprising:
 providing a substrate;   forming a first electrode on the substrate;   forming a first dielectric layer on the first electrode;   patterning the first dielectric layer to form a dielectric pillar, wherein the top view of the dielectric pillar is circle or polygon;   conformally forming a phase-change material to cover the dielectric pillar and etching back the phase-change material to remove phase-change material on the top surface of the dielectric pillar and first electrode,   remaining a phase-change material spacer on the side walls of the dielectric pillar;   forming a second dielectric layer on the substrate and subjected to a back-etched, covering the sidewalls of the phase-change material spacer; and   forming a second electrode on the dielectric pillar and second dielectric layer electrically connect to the phase-change material.   
     
     
         6 . The method as claimed in  claim 5 , wherein the phase-change material spacer has a width of 2 nm˜120 nm and a height of 1 mm˜200 nm. 
     
     
         7 . The method as claimed in  claim 5 , wherein at least one of the first electrode and the second electrode comprises phase-change material. 
     
     
         8 . The method as claimed in  claim 5 , wherein the top view of the phase-change material spacer is closed curve. 
     
     
         9 . The method as claimed in  claim 5 , after forming the phase-change material spacer, further comprising:
 patterning the phase-change material spacer to form a non-continuous phase-change material spacer.   
     
     
         10 . The method as claimed in  claim 5 , after forming the second electrode, further comprising:
 patterning the first electrode and the second electrode with the substrate acting as a etching-stop, and blanketly forming a third dielectric layer to surround the electrodes.   
     
     
         11 . The method as claimed in  claim 5 , wherein the first electrode and the second electrode are patterned by different patterning processes. 
     
     
         12 . The method as claimed in  claim 5 , wherein the dielectric pillar has a width of 20 nm˜500 nm. 
     
     
         13 . A method for fabricating phase-change memory element, comprising
 providing a substrate;   forming a first electrode on the substrate;   forming a first dielectric layer on the first electrode;   patterning the first dielectric layer to form an opening, wherein the top view of the opening is circle or polygon;   conformally forming a phase-change material on the first dielectric layer to cover the opening and etching back the phase-change material to remain a phase-change material spacer on the side walls of the opening;   forming a second dielectric layer on the substrate and subjected to a back-etched, covering the sidewalls of the phase-change material spacer; and   forming a second electrode on the opening and the second dielectric layer to electrically connect to the phase-change material spacer.   
     
     
         14 . The method as claimed in  claim 13 , wherein the phase-change material spacer has a width of 2 nm˜120 nm and a height of 1 nm˜200 nm. 
     
     
         15 . The method as claimed in  claim 13 , wherein at least one of the first electrode and the second electrode comprises phase-change material. 
     
     
         16 . The method as claimed in  claim 13 , wherein the top view of the phase-change material spacer is closed curve. 
     
     
         17 . The method as claimed in  claim 13 , after forming the phase-change material spacer, further comprising:
 patterning the phase-change material spacer to form a non-continuous phase-change material spacer.   
     
     
         18 . The method as claimed in  claim 13 , after forming the second electrode, further comprising:
 patterning the first electrode and the second electrode with the substrate acting as a etching-stop, and blanketly forming a third dielectric layer to surround the electrodes.   
     
     
         19 . The method as claimed in  claim 13 , wherein the first electrode and the second electrode are patterned by different patterning processes. 
     
     
         20 . The method as claimed in  claim 13 , wherein the opening has a width of 20 mm˜500 nm.