Single-Crystal Phase Change Material on Insulator for Reduced Cell Variability

Abstract

Techniques for producing a single-crystal phase change material and the incorporation of those techniques in an electronic device fabrication process flow are provided. In one aspect, a structure is provided having a substrate; an insulator over the substrate; and a single-crystal phase change material over the insulator. In another aspect, an electronic device is provided having a substrate; an insulator over the substrate; and a single-crystal phase change material over the insulator, wherein the single-crystal phase change material makes up a plurality of cells of the electronic device, each of the cells being configured to have one of two forms: 1) a first form consisting solely of single-crystal phase change material, and 2) a second form consisting of a region of single-crystal phase change material in contact with a region of amorphous phase change material.

What is claimed is: 
     
         1 . A structure, comprising:
 a substrate;   an insulator over the substrate; and   a single-crystal phase change material over the insulator.   
     
     
         2 . The structure of  claim 1 , wherein the single-crystal phase change material comprises a single-crystal epitaxial chalcogenide phase change material. 
     
     
         3 . The structure of  claim 2 , wherein the single-crystal epitaxial chalcogenide phase change material is an alloy comprising at least two of: antimony, tellurium, and germanium. 
     
     
         4 . An electronic device, comprising:
 a substrate;   an insulator over the substrate; and   a single-crystal phase change material over the insulator, wherein the single-crystal phase change material makes up a plurality of cells of the electronic device, each of the cells being configured to have one of two forms: 1) a first form consisting solely of single-crystal phase change material, and 2) a second form consisting of a region of single-crystal phase change material in contact with a region of amorphous phase change material.   
     
     
         5 . The electronic device of  claim 4 , wherein the single-crystal phase change material comprises a single-crystal epitaxial chalcogenide phase change material. 
     
     
         6 . The electronic device of  claim 5 , wherein the single-crystal epitaxial chalcogenide phase change material is an alloy comprising at least two of: antimony, tellurium, and germanium. 
     
     
         7 . The electronic device of  claim 4 , wherein the single-crystal epitaxial phase change material is an alloy comprising antimony and one of germanium or gallium. 
     
     
         8 . The electronic device of  claim 4 , further comprising:
 at least one first electrode in contact with a first side of the single-crystal phase change material; and   at least one second electrode in contact with a second side of the single-crystal phase change material, wherein the at least one first electrode and the at least one second electrode are configured to deliver current to the bits during operation of the device.   
     
     
         9 . The electronic device of  claim 4 , wherein each of the cells are configured to be switched between the two forms by running an electric current therethrough. 
     
     
         10 . The electronic device of  claim 4 , wherein a given one of the cells having the first form consisting solely of the single-crystal phase change material is configured to have a lower resistivity to electrical current than a given one of the cells having the second form consisting of the region of single-crystal phase change material in contact with the region of amorphous phase change material. 
     
     
         11 . The electronic device of  claim 10 , being configured to serve as a computer memory device, wherein the given one of the cells having the first form consisting solely of the single-crystal phase change material is configured to store a logical “1” and the given one of the cells having the second form consisting of the region of single-crystal phase change material in contact with the region of amorphous phase change material is configured to store a logical “0.”