Patent ID: 8872286

Claim:
A first and second metal gate structure located on a substrate, comprising: a gate dielectric layer located on the substrate; a barrier layer located on the gate dielectric layer; a first work function metal layer located on a part of the barrier layer; a second work function metal layer located on the barrier layer and the first work function metal layer, wherein the first work function metal layer, the second work function metal layer, and the gate dielectric layer all have a U-shaped profile structure; and a titanium aluminum nitride metal layer having a U-shaped profile structure directly located on the second work function metal layer, so that the first metal gate structure comprises the gate dielectric layer, the barrier layer, the first work function layer, the second work function metal layer and the titanium aluminum nitride metal layer, and the second metal gate structure comprises the gate dielectric layer, the barrier layer, the second work function metal layer and the titanium aluminum nitride metal layer.