Metal gate structure

摘要

The metal gate structure of the present invention can include a TiN complex, and the N/Ti proportion of the TiN complex is decreased from bottom to top. In one embodiment, the TiN complex can include a single TiN layer, which has an N/Ti proportion gradually decreasing from bottom to top. In another embodiment, the TiN complex can include a plurality of TiN layers stacking together. In such a case, the lowest TiN layer has a higher N/Ti proportion than the adjusted TiN layer.

主权项

1. A metal gate structure, comprising:
a gate dielectric layer; and a gate electrode, comprising
a first work function metal layer, disposed on the gate dielectric layer; anda second work function metal layer, disposed on the first work function metal layer; wherein both the first and the second work function metal layers are substantially composed by a first element and a second element, a ratio of the first element to the second element of the first work function metal layer is different from a ratio of the first element to the second element of the second work function metal layer, a ratio of the second element to the first element decreases along with a thickness of the first work function metal layer or a thickness of the second work function metal layer from bottom to top, and a molecular composition of the first work function metal layer and a molecular composition of the second work function metal layer are not continuous at an interface between the first work function metal layer and the second work function metal layer.