SEMICONDUCTOR DEVICE AND METHOD FOR FABRICATING THE SAME
A method for fabricating semiconductor device includes the steps of first providing a substrate having a first region and a second region, forming a first bottom barrier metal (BBM) layer on the first region and the second region, forming a first work function metal (WFM) layer on the first BBM layer on the first region and the second region, and then forming a diffusion barrier layer on the first WFM layer.
1 . A semiconductor device, comprising:
a substrate having a first region and a second region;
a gate structure on the first region and the second region of the substrate, wherein the gate structure comprises:
a first bottom barrier metal (BBM) layer on the first region and the second region;
a first work function metal (WFM) layer on the first region;
a diffusion barrier layer on the first WFM layer, wherein sidewalls of the diffusion barrier layer and the first WFM layer are aligned; and
a second WFM layer on the diffusion barrier layer, wherein the second WFM layer extends from a top surface of the diffusion barrier layer to sidewalls of the diffusion barrier layer and the first WFM layer.
2 . The semiconductor device of claim 1 , further comprising a low resistance metal layer on the second WFM layer.
3 . The semiconductor device of claim 1 , wherein the first WFM layer comprises a p-type WFM layer and the second WFM layer comprises a n-type WFM layer.
4 . The semiconductor device of claim 1 , wherein the first BBM layer and the diffusion barrier layer comprise a same material.
5 . The semiconductor device of claim 1 , further comprising a second BBM layer between the first BBM layer and the substrate.
6 . The semiconductor device of claim 5 , wherein the first BBM layer and the second BBM layer comprise different materials.