Resistor with improved switchable resistance and non-volatile memory device

Abstract

Provides a resistor with improved switchable resistance and non-volatile memory device. An example resistor includes a first electrode, a second electrode facing the first electrode and a resistance structure between the first electrode and the second electrode. The resistance structure includes an insulating dielectric material in which a confined switchable conductive region is formed between the first and second electrode. The resistor further includes a perturbation element, locally exerting mechanical stress on the resistance structure in the vicinity of the perturbation element at least during a forming process in which the confined switchable conductive region is formed.

1 . A resistor comprising: 
 a first electrode;    a second electrode facing the first electrode;    a resistance structure between the first electrode and the second electrode, the resistance structure comprising an insulating dielectric material in which a confined conductive region is formed between the first and the second electrode; and    a perturbation element locally exerting mechanical stress on the resistance structure in the vicinity of the perturbation element at least during a forming process in which the confined conductive region is formed.    
   
   
       2 . A resistor according to  claim 1 , wherein the perturbation element comprises one of an electrically conductive tip, point, and edge on the first electrode's surface directed towards the second electrode.  
   
   
       3 . A resistor according to  claim 1 , wherein the perturbation element comprises a local change of the structure of the first electrode or of the resistance structure.  
   
   
       4 . A resistor according to  claim 1 , wherein the perturbation element comprises one of: 
 a confined crystalline region in the first electrode whereas the first electrode is amorphous, and    a confined amorphous region in the first electrode whereas the first electrode is crystalline.    
   
   
       5 . A resistor according to  claim 1 , wherein the perturbation element comprises one of: 
 a confined crystalline region in the resistance structure whereas the resistance structure is amorphous, and    a confined amorphous region in the resistance structure whereas the resistance structure is crystalline.    
   
   
       6 . A resistor according to  claim 1 , wherein the perturbation element comprises a local variation of the composition or topology of the resistance structure.  
   
   
       7 . A resistor according to  claim 1 , wherein the perturbation element comprises a piezoelectric structure exerting mechanical stress on the resistance structure in the vicinity of the piezoelectric structure when a voltage is applied to the piezoelectric structure.  
   
   
       8 . A resistor according to  claim 1 , wherein the perturbation element comprises one of a particle, a precipitate of an other phase, an interstitial atom, and a microcrystallite embedded in the resistance structure.  
   
   
       9 . A resistor according to  claim 1 , wherein the perturbation element comprises a convex feature of, or on, the first electrode's surface adjacent to the resistance structure.  
   
   
       10 . A resistor according to  claim 9 , wherein a convex or concave member between the first electrode and a substrate constitutes a convex or concave shape of the first electrode towards the second electrode.  
   
   
       11 . A resistor according to  claim 1 , wherein the thickness of the resistance structure between the first electrode and the second electrode locally varies in the vicinity of the perturbation element.  
   
   
       12 . A resistor according to  claim 1 , wherein the confined conductive region provides a first resistance state and a second resistance state, and wherein the resistance state of the confined conductive region is switchable between the first resistance state and the second resistance state by a control signal.  
   
   
       13 . A non-volatile memory cell comprising a resistor according to  claim 12 , wherein the resistance state of the confined conducting region indicates the information stored in the memory cell.  
   
   
       14 . A non-volatile memory device comprising: 
 a non-volatile memory cell according to  claim 13;  and    a controller for writing and reading the memory cell.    
   
   
       15 . A non-volatile memory device according to  claim 14 , wherein the controller is provided for applying an electrical writing signal to the memory cell in order to write information into the memory cell and for applying an electrical reading signal to the memory cell in order to read information from the memory cell, wherein the reading signal is smaller than the control signal.  
   
   
       16 . A non-volatile memory device according to  claim 15 , wherein the control signal and the reading signal are voltage or current pulses.  
   
   
       17 . A method for fabricating an insulating dielectric structure with a confined conductive region through the insulating dielectric structure, wherein a confined strain field is generated at a predetermined position thereby providing a predetermined position for the confined conductive region.  
   
   
       18 . A method according to  claim 17 , wherein a perturbation element is produced which generates the confined strain field in its vicinity.  
   
   
       19 . A method according to  claim 18  wherein the perturbation element is produced by at least one of: growing, depositing, etching a dot on the surface of a substrate, and etching a dot on a layer over the substrate over which dot the insulating dielectric structure is deposited.  
   
   
       20 . A method according to  claim 18  wherein a metal region is provided adjacent to an electrode comprising doped amorphous silicon, the method further comprising a step of heating the electrode whereby a local crystallization of its material is induced, the locally crystallized material forming the perturbation element.  
   
   
       21 . A method for fabricating a resistor with bistable or multistable switchable resistance, comprising: 
 producing a first electrode;    producing an insulating dielectric structure according to  claim 17  adjacent to the first electrode, the confined conductive region providing a first resistance state and a second resistance state and the resistance state of the confined conductive region being switchable between the first resistance state and the second resistance state by a control signal, and    producing a second electrode adjacent to the insulating dielectric structure.    
   
   
       22 . A method for forming a confined conductive region in an insulating dielectric material, comprising: 
 applying a forming signal to the insulating dielectric material, and    activating a piezoelectric element in order to locally exert mechanical stress to the insulating dielectric material during the application of the forming signal.