Phase-change random access memory device and method of manufacturing the same

1. A phase-change random access memory (PRAM) device, comprising:

a semiconductor substrate in which a switching device is formed;

a lower electrode formed on the switching device and having a plurality of voids formed in an upper surface of the lower electrode; and

a phase-change layer formed on the lower electrode having the voids,

wherein a contact area between the lower electrode and the phase-change layer is reduced by the plurality of voids.

2. The PRAM device of claim 1 , wherein the lower electrode includes any one of titanium nitride (TiN) and titanium aluminum nitride (TiAlN).

3. The PRAM device of claim 2 , wherein the lower electrode is formed using at least one method selected among a chemical vapor deposition (CVD) method, an atomic layer deposition (ALD) method, and a physical vapor deposition (PVD).

4. The PRAM device of claim 3 , wherein the void is formed by a plasma-treated process using a reducing agent containing hydrogen ions or nitrogen ions.

5. The PRAM device of claim 4 , further comprising:

a spacer formed at an outer sidewall of the phase-change layer.

6. A method of fabricating a phase-change random access memory (PRAM) device, the method comprising:

forming a lower electrode on a semiconductor substrate using a reactive gas having a carbon;

performing reduction treatment on an upper surface of the lower electrode to form a plurality of voids in the upper surface of the lower electrode; and

forming a phase-change layer on the lower electrode,

wherein a contact area between the lower electrode and the phase-change layer is reduced by the plurality of voids.

7. The method of claim 6 , wherein the forming voids includes:

permeating a reducing agent into the upper surface of the lower electrode for reacting with the carbon of the lower electrode; and

performing plasma treatment on the upper surface of the lower electrode into which the reducing agent is permeated.

8. The method of claim 6 , wherein the forming the voids includes:

forming a metal oxide layer on the lower electrode using a reactive gas having a carbon;

permeating a reducing agent into a top of the metal oxide layer; and

performing plasma treatment on the upper surface of the lower electrode having the metal oxide layer into which the reducing agent is permeated.

9. The method of claim 7 , wherein the reducing agent includes any one of hydrogen ions and nitrogen ions.

10. The method of claim 8 , wherein the reducing agent includes any one of hydrogen ions and nitrogen ions.

11. A phase-change random access memory (PRAM) device, comprising:

a semiconductor substrate;

a switching device formed on the semiconductor substrate;

a lower electrode formed on the switching device and having an upper surface of the lower electrode having a plurality of voids; and

a phase-change layer configured to be formed on the lower electrode having the voids,

wherein the plurality of voids are generated by reducing of reactive ions for forming the low electrode, and

wherein a contact area between the lower electrode and the phase-change layer is reduced by the plurality of voids.

12. The phase-change random access memory (PRAM) device of claim 11 , wherein the voids comprise a number of nano (nm)-sized voids.

13. A method of fabricating a phase-change random access memory (PRAM) device, the method comprising:

providing a semiconductor substrate;

forming a lower electrode on the semiconductor substrate;

performing reduction treatment on an upper surface of the lower electrode to form a plurality of voids in the upper surface of the lower electrode; and

forming a phase-change layer on the lower electrode,

wherein the plurality of voids are generated by reducing of reactive ions for forming the low electrode, and

wherein a contact area between the lower electrode and the phase-change layer is reduced by the plurality of voids.

14. The method of claim 13 , wherein the voids comprise a number of nano (nm)-sized voids.