Variable resistive memory device and method of fabricating the same

1. A variable resistive memory device comprising:

an interlayer insulating film having an opening therein, the opening exposing a surface of a first electrode which is disposed at a bottom of the opening;

a variable resistive layer formed in the opening; and

a second electrode formed on the variable resistive layer,

wherein a sidewall of the variable resistive layer is separated from an inner side surface of the opening to define a gap between the sidewall of the variable resistive layer and the inner side surface of the opening.

2. The variable resistive memory device of claim 1 , wherein the first electrode is formed at the bottom of the opening.

3. The variable resistive memory device of claim 1 , wherein the variable resistive layer contacts a surface of the first electrode, except for a surface of a portion of the first electrode formed directly beneath the gap.

4. The variable resistive memory device of claim 1 , wherein the second electrode extends over a top surface of the interlayer insulating film to cover the gap.

5. The variable resistive memory device of claim 1 , wherein the gap is filled with oxygen, nitrogen, an inert gas, or a mixture thereof.

6. The variable resistive memory device of claim 1 , wherein the gap is evacuated.

7. The variable resistive memory device of claim 1 , wherein the variable resistive layer comprises a phase-change material layer.

8. The variable resistive memory device of claim 7 , wherein the phase-change material layer comprises a chalcogenide material.

9. The variable resistive memory device of claim 1 , further comprising a selection element positioned between any one of the first electrode and the second electrode and the variable resistive layer.

10. The variable resistive memory device of claim 1 , wherein the first electrode is coupled to a bit line or a word line, and the second electrode is coupled to the other one of the bit line or the word line.