Controlling ReRam forming voltage with doping
An internal electrical field in a resistive memory element can be formed to reduce the forming voltage. The internal electric field can be formed by incorporating one or more charged layers within the switching dielectric layer of the resistive memory element. The charged layers can include adjacent charge layers to form dipole layers. The charged layers can be formed at or near the interface of the switching dielectric layer with an electrode layer. Further, the charged layer can be oriented with lower valence substitution side towards lower work function electrode, and higher valence substitution side towards higher work function electrode.
1. A resistive memory device comprising
a first electrode having a first work function;
a second electrode having a second work function,
wherein the first work function is different from the second work function;
a dielectric layer,
wherein the dielectric layer is disposed between the first and second electrodes,
wherein the dielectric layer is operable as a switching layer,
wherein the dielectric layer comprises at least one charged layer,
wherein the at least one charged layer comprises two adjacent charged layers of opposite polarities to form a dipole layer.
2. A resistive memory device as in claim 1 wherein the work function difference between the first and second electrode is greater than 1 eV.
3. A resistive memory device as in claim 1 wherein the two adjacent charged layers are immediately next to each other.
4. A resistive memory device as in claim 1 wherein the separation between the two adjacent charges layers is between 0.3 and 3 nm.
5. A resistive memory device as in claim 1
wherein the at least one charged layer comprises elements having lower valence than that of a metal element of the dielectric layer, and wherein the elements having lower valence than that of a metal element of the dielectric layer can substitute on the metal element site;
wherein the at least one charged layer comprises elements having lower valence than that of oxygen, and wherein the elements having lower valence than that of oxygen can substitute on the oxygen site; or
wherein the at least one charged layer comprises elements having higher valence than that of oxygen.
6. A resistive memory device as in claim 5
wherein the elements having lower valence than that of a metal element of the dielectric layer comprise greater than 10 at % of substitution within the dielectric layer;
wherein the elements having lower valence than that of oxygen comprise greater than 30 at % of substitution within the dielectric layer; or
wherein the elements having higher valence than that of oxygen comprise greater than 30 at % of substitution within the dielectric layer.
7. A resistive memory device as in claim 1 wherein the at least one charged layer comprises less than 30% of the dielectric layer.
8. A resistive memory device as in claim 1 wherein the at least one charged layer comprises a charged layer located at a distance of less than 3 nm from an interface of the dielectric layer and the first or second electrode.
9. A resistive memory device as in claim 1 wherein the at least one charged layer comprises between 5 and 50% of the dielectric layer.