Memory elements and methods with improved data retention and/or endurance
View Patent ↗A method can include forming at least one memory layer over a first electrode, the memory layer having at least one element formed therein that oxidizes in the presence of an electric field to form conductive paths within the memory layer; and forming an inhibiting layer within the memory layer that increases an oxidation energy for the at least one element, as compared to the oxidation energy for the at least one element in the memory layer without the inhibiting layer.
1. A method, comprising:
forming at least one memory layer over a first electrode, the memory layer having at least one element formed therein that oxidizes in the presence of an electric field to form conductive paths within the memory layer; and
forming an inhibiting layer within the memory layer that increases an oxidation energy for the at least one element, as compared to the oxidation energy for the at least one element in the memory layer without the inhibiting layer.
2. The method of claim 1 , wherein:
the inhibiting layer is formed after the memory layer is formed.
3. The method of claim 1 , wherein:
the inhibiting layer is incorporated into the memory layer through a surface of the memory layer.
4. The method of claim 1 , further including:
forming a second electrode over the top surface of the memory layer.
5. The method of claim 1 , wherein:
forming the inhibiting layer includes forming a material is selected from the group of:
a hole scavenger that occupies a hole or increases a formation energy of a hole within the memory layer;
an electron scavenger that binds with free electrons within the memory layer;
a reducing agent that provides electrons for reducing ionic forms of the at least one element;
a scavenger of predetermined oxidizer precursors that binds with such oxidizer precursors, an oxidizer precursor being a compound that forms an oxidizing agent of the at least one element;
a scavenger of oxidizers that prevent such oxidizers from oxidizing the at least one element;
a scavenger of any of: halides, nitrides, nitrates, or sulfur oxides; and
a scavenger of a compound, or precursor of a compound, that forms an oxide of the at least one element.
6. The method of claim 1 , wherein:
forming the memory layer includes forming a layer of GeS 2 ; and
forming the inhibitor material includes forming a scavenger of any selected from the group of: sulfur with an oxidation state of −2 (S 2− ), HS—, or H 2 S.
7. The method of claim 1 , wherein:
the memory layer comprises a metal oxide.
8. A method, comprising:
incorporating at least one inhibitor compound into a memory layer of a memory element in which conductive regions are formed and dissolved, the inhibitor compound increasing energy needed to oxidize clusters of at least one element formable within the solid electrolyte by application of an electric field to create the conductive regions.
9. The method of claim 8 , wherein:
the at least one inhibitor compound decreases ionic mobility of at least one oxidized element within the memory layer.
10. The method of claim 8 , wherein:
the at least one inhibitor compounds decreases mobility of electrons within the memory layer.
11. The method of claim 8 , further including:
forming the memory layer between an active electrode layer and an indifferent electrode layer, the active electrode layer comprising the at least one element; and
incorporating the at least one inhibitor compound into a portion of the memory layer proximate to the active electrode; wherein
a portion of the memory layer proximate the indifferent electrode does not substantially include the inhibitor.
12. The method of claim 8 , wherein:
the inhibitor compound is selected from the group of:
a hole scavenger that occupies a hole or increases a formation energy of a hole within the memory layer;
an electron scavenger that binds with free electrons within the memory layer;
a reducing agent that provides electrons for reducing ionic forms of the at least one element;
a scavenger of predetermined oxidizer precursors that binds with such oxidizer precursors, an oxidizer precursor being a compound that forms an oxidizing agent of the at least one element;
a scavenger of oxidizers that prevent such oxidizers from oxidizing the at least one element;
a scavenger of any of: halides, nitrides, nitrates, or sulfur oxides; and
a scavenger of a compound, or precursor of a compound, that forms an oxide of the at least one element.
13. The method of claim 8 , wherein:
forming the memory layer comprises forming a metal oxide.
14. A method, comprising:
forming a memory material formed between two electrodes, where the forming of the memory material comprises
including in the memory material at least one element that is oxidizable in the presence of an electric field applied across the electrodes, and
including an inhibitor material incorporated into at least a portion of the memory material that decreases an oxidation rate of the at least one element within the memory material with respect to the memory material alone.
15. The method of claim 14 , wherein:
forming the memory material includes
forming the memory material in contact with a first of the electrodes at a first surface and in contact with a second of the electrodes at a second surface, and
including the inhibitor material to extend into only a portion of the memory material from the first surface.
16. The method of claim 14 , wherein:
the inhibitor material is selected from the group of:
a hole scavenger that occupies a hole or increases a formation energy of a hole within the memory material;
an electron scavenger that binds with free electrons within the memory material;
a reducing agent that provides electrons for reducing ionic forms of the at least one element;
a scavenger of predetermined oxidizer precursors that binds with such oxidizer precursors, an oxidizer precursor being a compound that forms an oxidizing agent of the at least one element;
a scavenger of oxidizers that prevent such oxidizers from oxidizing the at least one element; and
a scavenger of any compound selected from the group of: halides, nitrides, nitrates, or sulfur oxides.
17. The method of claim 14 , wherein:
the inhibitor material is a scavenger of a compound, or precursor of a compound, that forms an oxide of the at least one element.
18. The memory element of claim 14 , wherein
the inhibitor material is selected from the group of: tin chloride (SnCl 2 ), thirourea (SC(NH 2 ) 2 ), cyanine, a heterocyclic compound including a suitable mercapto tetrazole, a nitrite comprising NO 2 − with a selected cation, a nitrite, a sulfite, a hydroquinone, a carbohydrazide, a nitrite, a sulfite, a hydroquinone, and a carbohydrazide.
19. The memory element of claim 14 , wherein:
the at least one element is selected from: silver and copper.
20. The method of claim 14 , wherein:
forming the memory material includes forming a metal oxide.