Phase change memory element with a peripheral connection to a thin film electrode and method of manufacture thereof

Abstract

A PCM cell structure comprises a first electrode, a phase change element, and a second electrode, wherein the phase change element is inserted in between the first electrode and the second electrode and only the peripheral edge of one of the first and second electrodes contacts the phase change element thereby reducing the contact area between the phase change element and one of the electrodes thereby increasing the current density through the phase change element and effectively inducing the phase change at a first programming power.

1 . A phase change memory cell structure comprising: 
 a phase change element; and    a thin film electrode having a periphery;    wherein said phase change element is electrically connected to at least a portion of said periphery of said thin film electrode.    
   
   
       2 . The phase change memory cell structure of  claim 1 , wherein said thin film electrode comprises an annulus formed by deposition of a thin film onto inner sidewalls of a previously-fabricated cavity in the surface of an insulating film.  
   
   
       3 . The phase change memory cell structure of  claim 1 , wherein: 
 said thin film electrode comprises an annulus disposed at an angle with respect to a surface of said phase change element,    said thin film electrode includes a portion oriented so that its contact with the phase change element provides a conductive shunting path to modulate the variation in read resistance as said phase change element is switched between high and low resistance states.    
   
   
       4 . The phase change memory cell structure of  claim 1 , wherein: 
 said thin film electrode comprises a planar structure, and    said phase change element is electrically connected to said periphery of said thin film electrode.    
   
   
       5 . The phase change memory cell structure of  claim 4 , wherein: 
 said thin film electrode is oriented so that its contact with said phase change element provides a conductive shunting path to modulate variations in read resistance as said phase change element is switched between high and low resistance states.    
   
   
       6 . A phase change memory cell, comprising: 
 a phase change element;    a first electrode;    a second electrode; and    said phase change element being located between said first electrode and said second electrode in electrical and mechanical contact therewith at least one of said first electrode and said second electrode having a periphery with at least a portion thereof being in contact with said phase change element.    
   
   
       7 . The phase change memory cell structure of  claim 6 , wherein said thin film electrode comprises an annulus formed by deposition of a thin film onto inner sidewalls of a previously-fabricated cavity in a surface of an insulating film.  
   
   
       8 . The phase change memory cell structure of  claim 6 , wherein: 
 said thin film electrode comprises an annulus disposed at an angle with respect to a surface of said phase change element,    said thin film electrode includes a portion oriented so that contact thereof with said phase change element provides a conductive shunting path to modulate variations in read resistance as said phase change element is switched between high and low resistance states.    
   
   
       9 . The phase change memory cell structure of  claim 6 , wherein: 
 said thin film electrode comprises a planar structure with a periphery, and    said phase change element is in electrical contact with said periphery of said thin film electrode.    
   
   
       10 . The phase change memory cell structure of  claim 9 , wherein: 
 said thin film electrode is oriented so that said contact with said phase change element provides a conductive shunting path to modulate variations in read resistance as said phase change element is switched between high and low resistance states.    
   
   
       11 . A method of forming a phase change memory cell structure comprising: 
 forming a thin film electrode having a periphery; and    forming a phase change element over said periphery of said thin film electrode;    wherein said phase change element is electrically connected to at least a portion of said periphery of said thin film electrode.    
   
   
       12 . The method of  claim 11 , wherein said thin film electrode comprises an annulus formed by deposition of a thin film onto inner sidewalls of a previously-fabricated cavity in the surface of an insulating film.  
   
   
       13 . The method of  claim 11  wherein: 
 said thin film electrode comprises an annulus disposed at an angle with respect to a surface of said phase change element,    said thin annulus electrode includes a portion oriented so that its contact with the phase change element provides a conductive shunting path to modulate the variation in read resistance as said phase change element is switched between high and low resistance states.    
   
   
       14 . The method of  claim 11 , wherein: 
 said thin film electrode comprises a planar structure, and    said phase change element is electrically connected to said periphery of said thin film electrode.    
   
   
       15 . The method of  claim 14 , wherein: 
 said thin film electrode is oriented so that its contact with said phase change element provides a conductive shunting path to modulate variations in read resistance as said phase change element is switched between high and low resistance states.    
   
   
       16 . A method of forming a phase change memory cell, comprising: 
 forming a first electrode;    forming a second electrode forming a phase change element; and    forming said phase change element between said first electrode and said second electrode in electrical and mechanical contact therewith at least one of said first electrode and said second electrode having a periphery with at least a portion thereof being in contact with said phase change element.    
   
   
       17 . The method of  claim 16 , wherein said thin film electrode comprises an annulus formed by deposition of a thin film onto inner sidewalls of a previously-fabricated cavity in a surface of an insulating film.  
   
   
       18 . The method of  claim 16 , wherein: 
 said thin film electrode comprises an annulus disposed at an angle with respect to a surface of said phase change element,    said thin annulus electrode includes a portion oriented so that contact thereof with said phase change element provides a conductive shunting path to modulate variations in read resistance as said phase change element switches between high and low resistance states.    
   
   
       19 . The method of  claim 16  wherein: 
 said thin film electrode comprises a planar structure, and a phase change element is in electrical contact with said periphery of said thin film electrode.    
   
   
       20 . The method of  claim 19  including: 
 orienting said thin film electrode so that said contact with said phase change element provides a conductive shunting path to modulate variations in read resistance as said phase change element is switched between high and low resistance states.