Memory cell structures

1. A memory cell, comprising:

a storage element between a first electrode and a second electrode, wherein filament nucleation for the storage element is achieved between where a blunted peak of the first electrode contacts the storage element and where a contact portion of the second electrode contacts the storage element, wherein the first electrode includes angled sidewalls that converge toward the storage element, wherein a planar surface of the blunted peak of the first electrode contacts a first surface of the storage element between the angled sidewalls of the first electrode, wherein the contact portion includes sidewalls that converge and meet at a second surface of the storage element, wherein a largest dimension of the planar surface of the first electrode is oriented in a first direction and a largest dimension of a planar surface of the second electrode adjacent to the contact portion is oriented in a second direction that is substantially orthogonal to the first direction, and wherein the planar surface of the blunted peak of the first electrode that contacts the first surface of the storage element in the first direction is substantially orthogonal to the contact portion of the second electrode that contacts the second surface of the storage element in the second direction.

2. The memory cell of claim 1 , wherein the second electrode is formed on the second surface of the storage element.

3. The memory cell of claim 1 , wherein the first electrode has a cross-sectional area selected from the group consisting of trapezoidal or triangular.

4. The memory cell of claim 1 , wherein the first electrode has sidewalls that are selected from the group consisting of straight, concave, or convex.

5. The memory cell of claim 1 , wherein a top surface of the first electrode is an electrode contact portion of the first electrode and is in contact with the storage element.

6. The memory cell of claim 1 , wherein sidewalls of the first electrode converge toward the storage element.

7. The memory cell of claim 1 , wherein the storage element includes a resistance variable material.

8. The memory cell of claim 1 , wherein the first electrode is a bottom electrode conductor line.

9. A method of operating a memory cell, comprising:

applying a voltage to the memory; and

forming an active region of the memory cell by causing filament nucleation in the storage element between the first electrode and the second electrode, wherein the first electrode includes angled sidewalls that converge toward the storage element, wherein the filament nucleation occurs between a planar surface of the first electrode that contacts a first surface of the storage element and a second surface of the storage element where angled sidewalls of a contact portion of the second electrode converge and meet, wherein a largest dimension of the planar surface of the first electrode is oriented in a first direction and a largest dimension of a planar surface of the second electrode adjacent to the contact portion is oriented in a second direction that is substantially orthogonal to the first direction, and wherein the planar surface of the first electrode that contacts the first surface of the storage element in the first direction is substantially orthogonal to the contact portion of the second electrode that contacts the second surface of the storage element in the second direction.

10. The method of claim 9 , wherein forming the active region of the memory cell includes localizing the active region between a blunted peak of the first electrode that contacts the storage element and the contact portion of the second electrode that contacts the storage element.

11. The method cell of claim 9 , wherein applying the voltage to the memory cell includes applying a programming signal to the memory cell.

12. The method of claim 9 , wherein forming the active region of the memory cell includes causing filament nucleation in the storage element between a blunted peak of the first electrode that is closest to the contact portion of the second electrode.

13. The method of claim 9 , further including applying another voltage to the memory cell to sense a state of the memory cell once the active region of the memory cell has been formed.

14. A method of forming a memory cell, comprising:

forming a first electrode including a peak;

forming a storage element on the peak of the first electrode such that the storage element has a peak, wherein the peak of the first electrode contacts the storage element; and

forming a second electrode on the storage element such that a contact portion of the second electrode contacts the peak of the storage element, wherein an active region of the storage element is between the first electrode and the second electrode, wherein the contact portion includes a first sidewall and a second sidewall that converge toward a surface of the storage element between the peak of the first electrode and the peak of the storage element, and wherein the peak of the first electrode that contacts the storage element is substantially orthogonal to a surface of the contact portion of the second electrode that contacts the peak of the storage element.

15. The method of claim 14 , wherein the method includes forming a dielectric material adjacent to the sidewalls of the first electrode.

16. The method of claim 14 , wherein the method includes achieving filament nucleation for the storage element between a portion of the first electrode that contacts the storage element and the contact portion of the second electrode that contacts the storage element.