Semiconductor device and method for fabricating the same

1. A method for fabricating a capacitor, the method comprising:

forming a bottom electrode;

forming a dielectric layer on the bottom electrode;

forming a metal oxide layer including a metal having a high electronegativity on the dielectric layer;

forming a sacrificial layer on the metal oxide layer to reduce the metal oxide layer to a metal layer; and

forming a top electrode on the sacrificial layer to convert the reduced metal layer into a high work function interface layer.

2. The method of claim 1 , wherein the forming of the sacrificial layer on the metal oxide layer is performed under a hydrogen gas atmosphere.

3. The method of claim 1 , wherein the forming of the sacrificial layer on the metal oxide layer includes:

forming a silicon layer on the metal oxide layer using a hydrogen-containing silicon source gas under a hydrogen gas atmosphere.

4. The method of claim 1 , wherein the forming of the sacrificial layer on the metal oxide layer includes:

forming a doped silicon layer on the metal oxide layer using a hydrogen-containing silicon source gas and a hydrogen-containing dopant gas under a hydrogen gas atmosphere.

5. The method of claim 1 , wherein the forming of the sacrificial layer on the metal oxide layer includes:

forming a silicon oxide layer on the metal oxide layer; and

forming a silicon layer on the silicon oxide layer using a hydrogen-containing silicon source gas under a hydrogen gas atmosphere.

6. The method of claim 5 , wherein the forming of the silicon oxide layer on the metal oxide layer includes:

forming a laminate structure by alternatively depositing the metal oxide layer and the silicon oxide layer.

7. The method of claim 1 , wherein the forming of the top electrode on the sacrificial layer includes:

forming a silicon germanium layer doped with an impurity on the sacrificial layer.

8. The method of claim 1 , wherein the forming of the top electrode on the sacrificial layer is performed at a temperature such that the sacrificial layer and the reduced metal layer react to form a metal silicide layer or a metal germanide.

9. The method of claim 1 , wherein the metal oxide layer includes a nickel oxide, the reduced metal layer includes a nickel layer, and the high work function interface layer includes a nickel silicide or a nickel-rich nickel silicide.

10. The method of claim 1 , wherein the metal oxide layer includes a cobalt oxide, the reduced metal layer includes a cobalt layer, and the high work function interface layer includes a cobalt silicide or a cobalt-rich cobalt silicide.

11. The method of claim 1 , wherein the metal oxide layer includes a tungsten oxide, the reduced metal layer includes a tungsten layer, and the high work function interface layer includes a tungsten silicide or a tungsten-rich silicide.

12. The method of claim 1 , wherein the forming of the sacrificial layer on the metal oxide layer includes:

forming a germanium layer on the metal oxide layer using a hydrogen-containing germanium source gas under a hydrogen gas atmosphere.

13. The method of claim 1 , wherein the forming of the sacrificial layer on the metal oxide layer includes:

forming a doped germanium layer on the metal oxide layer using a hydrogen-containing germanium source gas and a hydrogen-containing dopant gas under a hydrogen gas atmosphere.

14. The method of claim 1 , wherein the forming of the sacrificial layer on the metal oxide layer includes:

forming a germanium oxide layer on the metal oxide layer; and

forming a germanium layer on the germanium oxide layer using a hydrogen-containing germanium source gas under a hydrogen gas atmosphere.

15. The method of claim 14 , wherein the forming of the germanium oxide layer on the metal oxide layer includes:

forming a laminate structure by alternatively depositing the metal oxide layer and the germanium oxide layer.

16. The method of claim 1 , wherein the metal oxide layer includes a nickel oxide, the reduced metal layer includes a nickel layer, and the high work function interface layer includes a nickel germanide.

17. The method of claim 1 , wherein the metal oxide layer includes a cobalt oxide, the reduced metal layer includes a cobalt layer, and the high work function interface layer includes a cobalt germanide.

18. The method of claim 1 , wherein the metal oxide layer includes a tungsten oxide, the reduced metal layer includes a tungsten layer, and the high work function interface layer includes a tungsten germanide.

19. The method of claim 1 , wherein the dielectric layer includes a zirconium oxide, an aluminum oxide, or a combination thereof.

20. The method of claim 1 , wherein the bottom electrode includes a titanium nitride, and the top electrode includes a boron-doped silicon germanium layer.