SWITCH BASED ON PHASE-CHANGE MATERIAL

1 . A device, comprising:

a switch that includes a phase-change material, the switch including:

first and second conduction electrodes;

first and second regions of the phase-change material each coupled to the first and second conduction electrodes of the switch, the second region being located above the first region; and

a heating element being between first and second regions of the phase-change material and electrically insulated from the first and second regions of the phase-change material; and

a plurality of pillars extending in the first region of the phase-change material, the pillars being made of a material having a thermal conductivity greater than that of the phase-change material.

2 . The device according to claim 1 , wherein the first region is on top of and in contact with the first and second electrodes.

3 . The device according to claim 2 , wherein the second region is coupled to the first and second electrodes by vias.

4 . The device according to claim 3 , wherein the vias are in contact, by respective upper surfaces, with a lower surface of the second region of the phase-change material.

5 . The device according to claim 2 , wherein the second region of the phase-change material is under and in contact with third and fourth electrodes.

6 . The device according to claim 5 , wherein the third and fourth electrodes are respectively coupled to the first and second electrodes by vias.

7 . The device according to claim 1 , wherein the heating element is tungsten or of titanium nitride.

8 . The device according to claim 1 , comprising a plurality of pillars extending in the second region of the phase-change material, the pillar(s) being made of a material having a thermal conductivity greater than that of the phase-change material.

9 . A device, comprising:

a substrate;

a first and second electrode on the substrate;

a first phase change layer on the first and second electrode;

a heating element on the first phase change layer;

a second phase change layer on the heating element, the heating element being between the first and second phase change layer.

10 . The device of claim 9 , comprising a plurality of pillars extending in the first phase change layer, the pillars being made of a material having a thermal conductivity greater than that of the first phase change layer.

11 . The device of claim 10 , comprising a third and fourth electrode on the second phase change layer.

12 . The device of claim 11 , comprising a first via between the third electrode and the first electrode.

13 . The device of claim 12 , comprising a second via between the fourth electrode and the second electrode.

14 . A method, comprising;

forming a first and second electrode on a substrate;

forming a first phase change layer on the first and second electrode;

forming a heating element on the first phase change layer;

forming a second phase change layer on the heating element, the heating element being between the first and second phase change layer.

15 . The method of claim 14 , wherein forming the first and second electrode includes forming the first electrode spaced from the second electrode by a dimension and forming the first phase change layer overlapping the first electrode, the second electrode, and completely over the dimension between the first and second electrodes.

16 . The method of claim 15 , comprising forming a first insulating layer on the first phase change layer and forming a second insulating layer on the first insulating layer, on the first electrode, and on the second electrode.

17 . The method of claim 16 , comprising forming a third electrode and a fourth electrode on the second phase change layer.

18 . The method of claim 17 , comprising forming a first via coupling the third electrode and the first electrode and forming a second via coupling the fourth electrode to the second electrode.