Integrated circuit having memory having a step-like programming characteristic

1. An integrated circuit having a memory comprising:

a first electrode;

a second electrode; and

contiguous resistivity changing material between the first electrode and the second electrode, the resistivity changing material having a step-like programming characteristic.

2. The integrated circuit of claim 1 , wherein the resistivity changing material forms a step-like pattern.

3. The integrated circuit of claim 2 , wherein the resistivity changing material comprises a plurality of rectangular or cylindrical portions.

4. The integrated circuit of claim 1 , further comprising:

an insulation material laterally surrounding the resistivity changing material, the first electrode, and the second electrode.

5. The integrated circuit of claim 1 , further comprising:

a first dielectric material laterally surrounding at least a portion of the resistivity changing material, the first dielectric material having a first thermal conductivity; and

a second dielectric material laterally surrounding the first dielectric material, the first electrode, and the second electrode, the second dielectric material having a second thermal conductivity greater than the first thermal conductivity.

6. The integrated circuit of claim 5 , wherein the first dielectric material comprises a low-k material.

7. A memory cell comprising:

a first electrode;

a second electrode; and

a plurality of phase change material portions between the first electrode and the second electrode, each of the phase change material portions directly contacting another of the phase change material portions,

wherein a current density through one of the phase change material portions is different from a current density through another of the phase change material portions.

8. The memory cell of claim 7 , wherein each of the phase change material portions forms one of a rectangular shape and a cylindrical shape.

9. The memory cell of claim 7 , wherein at least two of the phase change material portions have different cross-sectional widths.

10. The memory cell of claim 7 , further comprising:

an insulation material laterally surrounding the phase change material portions, the first electrode, and the second electrode.

11. The memory cell of claim 7 , further comprising:

a first dielectric material laterally surrounding at least one of the phase change material portions, the first dielectric material having a first thermal conductivity; and

a second dielectric material laterally surrounding the first dielectric material, the first electrode, and the second electrode, the second dielectric material having a second thermal conductivity greater than the first thermal conductivity.

12. The memory cell of claim 11 , wherein the first dielectric material comprises a low-k material.

13. A memory cell comprising:

a first electrode;

a second electrode; and

a plurality of phase change material layers between the first electrode and the second electrode, the phase change material layers forming a step-like pattern, each of the phase change material layers directly contacting another of the phase change material layers,

wherein at least two of the phase change material layers comprise different phase change materials.

14. The memory cell of claim 13 , wherein at least two of the phase change material layers have different crystallization temperatures.

15. The memory cell of claim 13 , wherein each of the phase change material layers forms one of a rectangular shape and a cylindrical shape.

16. The memory cell of claim 13 , wherein at least two of the phase change material layers have different cross-sectional widths.

17. The memory cell of claim 13 , further comprising:

an insulation material laterally surrounding the phase change material layers, the first electrode, and the second electrode.

18. The memory cell of claim 13 , further comprising:

a first dielectric material laterally surrounding at least one of the phase change material layers, the first dielectric material having a first thermal conductivity; and

a second dielectric material laterally surrounding the first dielectric material, the first electrode, and the second electrode, the second dielectric material having a second thermal conductivity greater than the first thermal conductivity.

19. The memory cell of claim 18 , wherein the first dielectric material comprises a low-k material.