Semiconductor device and method of manufacturing the same

1. A method of forming a semiconductor device, comprising:

forming an interfacial layer on a semiconductor substrate;

forming a high-k dielectric on the interfacial layer;

forming a barrier metal on the high-k dielectric;

forming a poly-silicon layer on the barrier metal,

patterning the interfacial layer, the high-k dielectric, the barrier metal and the poly-silicon to form a gate stack forming spacers, extension regions, sidewalls and source/drain regions,

forming an interlayer dielectric on the gate stack;

etching off a portion of the interlayer dielectric to expose the poly-silicon layer;

forming an impurity metal layer, which includes an impurity metal having a barrier effect to the diffusive material, and a metal layer including a diffusive material, on the poly-silicon layer; and

converting the poly-silicon layer into a silicide containing the impurity metal, wherein the barrier metal comprises a titanium nitride (TiN) or a tantalum nitride (TaN).

2. The method of forming a semiconductor device, as claimed in claim 1 , wherein the impurity material is locally located so that a peak of the concentration of the impurity metal is located at a boundary between the barrier metal and the silicide gate.

3. The method of forming a semiconductor device, as claimed in claim 1 , wherein the high-k dielectric includes a Hf-based high-k dielectric or Zr-based high-k dielectric.

4. The method of forming a semiconductor device, as claimed in claim 1 , wherein barrier metal has a thickness of 3 nm or less.

5. The method of forming a semiconductor device, as claimed in claim 4 , wherein the thickness of the barrier metal comprises a thickness of 1.5 nm or less.

6. The method of forming a semiconductor device, as claimed in claim 1 , wherein the diffusive material includes Ni.

7. The method of forming a semiconductor device, as claimed in claim 1 , wherein the impurity metal comprises Pt or Al.