Resistive random access memory devices with extremely reactive contacts

1. A resistive switching device, comprising:

a first electrode selected from the group consisting of Pt, Mo, W, Cu, Ag, Au, TiN, Pd and combinations thereof;

a transition metal oxide layer formed on and physically contacting the first electrode, the transition metal oxide layer having a composition selected from the group consisting of hafnium dioxide, zirconium dioxide, and combinations thereof; and

an oxygen scavenging electrode formed on the transition metal oxide, the oxygen scavenging electrode having a different composition than the first electrode, the oxygen scavenging electrode selected from the group consisting of Er, La, Y, Yb, Sc, Ce, Pr, Nd, Sm, Dy, Ho, Tm, Lu and combinations thereof, wherein the oxygen scavenging electrode removes oxygen from the transition metal oxide layer to increase formation of oxygen vacancies in the transition metal oxide layer to enable a switching mode when a bias is applied between the first electrode and the oxygen scavenging electrode.

2. The device as recited in claim 1 , wherein the oxygen scavenging electrode includes erbium.

3. The device as recited in claim 1 , wherein the transition metal oxide layer includes hafnium dioxide.

4. The device as recited in claim 1 , wherein the resistive switching device forms a resistive random access memory cell.

5. The device as recited in claim 1 , wherein the bias includes a plurality of voltages and the resistive switching device stores at least two states corresponding to said plurality of voltages.

6. The device as recited in claim 1 , wherein the oxygen scavenging electrode includes a thickness of between about 1 nm and about 100 nm.

7. A resistive random access memory cell, comprising:

a first electrode formed on a substrate, the first electrode selected from the group consisting of Pt, Mo, W, Cu, Ag, Au, TiN, Pd and combinations thereof;

a transition metal oxide layer having a composition selected from the group consisting of hafnium dioxide, zirconium dioxide, silicon dioxide and combinations thereof, the transition metal oxide layer formed on and physically contacting the first electrode;

an oxygen scavenging electrode formed on the transition metal oxide, the oxygen scavenging electrode having a different composition than the first electrode, the oxygen scavenging electrode selected from the group consisting of Er, La, Y, Yb, Sc, Ce, Pr, Nd, Sm, Dy, Ho, Tm, Lu and combinations thereof; and

a biasing circuit integrated on the substrate and coupled to the first electrode and the oxygen scavenging electrode and configured to apply a bias voltage between the first electrode and the oxygen scavenging electrode wherein, when the device is biased, the oxygen scavenging electrode removes oxygen from the transition metal oxide layer to increase formation of oxygen vacancies in the transition metal oxide layer to enable a switching mode in accordance with the bias voltage.

8. The cell as recited in claim 7 , wherein the oxygen scavenging electrode includes erbium.

9. The cell as recited in claim 7 , wherein the transition metal oxide layer includes hafnium dioxide.

10. The cell as recited in claim 7 , wherein the bias voltage includes a plurality of voltages and the resistive random access memory cell stores at least two states corresponding to said plurality of voltages.

11. The cell as recited in claim 7 , wherein the oxygen scavenging electrode includes a thickness of between about 1 nm and about 100 nm.