Semiconductor device with metal gate structure comprising work-function metal layer and work-fuction adjustment layer
The present disclosure provides a semiconductor device with a profiled work-function metal gate electrode. The semiconductor structure includes a metal gate structure formed in an opening of an insulating layer. The metal gate structure includes a gate dielectric layer, a barrier layer, a work-function meta layer between the gate dielectric layer and the barrier layer and a work-function adjustment layer over the barrier layer, wherein the work-function metal has an ordered grain orientation. The present disclosure also provides a method of making a semiconductor device with a profiled work-function metal gate electrode.
1. A semiconductor device comprising:
a metal gate structure formed in an opening of an insulating layer, the metal gate structure comprising:
a gate dielectric layer in physical contact with a source/drain region of the semiconductor device;
a work-function metal layer over the gate dielectric layer;
a barrier layer over the work-function metal layer, wherein an interior perimeter of the barrier layer defines an area; and
a work-function adjustment layer over the barrier layer and filling the area defined by the interior perimeter of the barrier layer, wherein:
the barrier layer is in physical contact with the work-function metal layer and the work-function adjustment layer.
2. The semiconductor device of claim 1 , comprising a capping layer between the gate dielectric layer and the work-function metal layer.
3. The semiconductor device of claim 2 , wherein the capping layer is in physical contact with the work-function metal layer.
4. The semiconductor device of claim 1 , wherein the work-function metal layer comprises a crystallized metal.
5. The semiconductor device of claim 1 , wherein the work-function metal layer comprises at least one of TiAl or TiAl 3 .
6. The semiconductor device of claim 1 , wherein the work-function metal layer has a thickness of about 10 to about 100 angstroms.
7. The semiconductor device of claim 1 , wherein the work-function adjustment layer comprises Aluminum.
8. The semiconductor device of claim 1 , wherein the gate dielectric layer comprises a high-k material.
9. A semiconductor device comprising:
a metal gate structure formed in an opening in an insulating layer, the metal gate structure comprising:
a gate dielectric layer having a u-shaped profile;
a work-function metal layer over the gate dielectric layer and having a u-shaped profile;
a barrier layer over the work-function metal layer and having a u-shaped profile, wherein an interior perimeter of the barrier layer defines an area; and
a work-function adjustment layer over the barrier layer and filling the area defined by the interior perimeter of the barrier layer, wherein:
the barrier layer is in physical contact with the work-function metal layer and the work-function adjustment layer.
10. The semiconductor device of claim 9 , wherein the work-function metal layer is crystallized.
11. The semiconductor device of claim 9 , wherein the work-function metal layer is TiAl or TiAl 3 .
12. The semiconductor device of claim 9 , wherein the work-function metal layer has a thickness of 10 to 100 angstroms.
13. The semiconductor device of claim 9 , wherein the work-function adjustment layer is Aluminum.
14. A semiconductor device comprising:
a metal gate structure over an active region of the semiconductor device; the metal gate structure comprising:
a gate dielectric layer in physical contact with the active region;
a work-function metal layer over the gate dielectric layer;
a barrier layer over the work-function metal layer; and
a work-function adjustment layer over the barrier layer, wherein:
the barrier layer comprises trace metal from a diffusion of metal from the work-function adjustment layer into the work-function metal layer,
the barrier layer is in physical contact with the work-function metal layer and the work-function adjustment layer, and
the work-function adjustment layer completely fills an area defined by an interior perimeter of the barrier layer.
15. The semiconductor device of claim 14 , wherein the work-function metal layer has an ordered grain orientation.
16. The semiconductor device of claim 14 , wherein the work-function metal layer comprises a crystallized metal.
17. The semiconductor device of claim 14 , comprising a capping layer between the gate dielectric layer and the work-function metal layer.
18. The semiconductor device of claim 17 , wherein the capping layer is in physical contact with the gate dielectric layer and the work-function metal layer.
19. The semiconductor device of claim 14 , wherein the work-function metal layer is TiAl 3 .
20. The semiconductor device of claim 14 , wherein the work-function adjustment layer is Aluminum, Tungsten, or Copper.