Abstract: A semiconductor structure includes a substrate, a channel region, a gate structure, and source/drain regions. The channel region is over the substrate. The gate structure is over the channel region, and includes a high-k dielectric layer, a tungsten layer over the high-k dielectric layer, and a fluorine-containing work function layer over the tungsten layer. The source/drain regions are at opposite sides of the channel region.

Abstract: A semiconductor device includes a substrate, a semiconductor fin, a gate structure, and source/drain structures. The semiconductor fin extends upwardly from the substrate. The gate structure is across the semiconductor fin and includes a high-k dielectric layer over the semiconductor fin, a fluorine-containing work function layer over the high-k dielectric layer and comprising fluorine, a tungsten-containing layer over the fluorine-containing work function layer, and a metal gate electrode over the tungsten-containing layer. The source/drain structures are on the semiconductor fin and at opposite sides of the gate structure.

Abstract: A semiconductor device includes a substrate, a semiconductor fin, a gate structure, and source/drain structures. The semiconductor fin extends upwardly from the substrate. The gate structure is across the semiconductor fin and includes a high-k dielectric layer over the semiconductor fin, a fluorine-containing work function layer over the high-k dielectric layer and comprising fluorine, a tungsten-containing layer over the fluorine-containing work function layer, and a metal gate electrode over the tungsten-containing layer. The source/drain structures are on the semiconductor fin and at opposite sides of the gate structure.

Abstract: A high-k dielectric layer is formed over a semiconductor substrate having a first trench and a second trench. A barrier layer is formed over the high-k dielectric layer. A work function layer is deposited over the barrier layer, and is patterned and removed from the second trench, exposing the barrier layer at the second trench. A precursor is deposited selectively over the barrier layer in the second trench, and deposited over the work function layer in the first trench. The precursor selectively reacts with the barrier layer to selectively etch the barrier layer, and selectively reacts with the work function layer to selectively etch a top oxidized portion of the work function layer and deposit a protective layer. The reaction products between the precursor and the barrier layer, and the reaction products between the precursor and the work function layer are removed by using an inert gas.

Abstract: A high-k dielectric layer is formed over a semiconductor substrate having a first trench and a second trench. A barrier layer is formed over the high-k dielectric layer. A work function layer is deposited over the barrier layer, and is patterned and removed from the second trench, exposing the barrier layer at the second trench. A precursor is deposited selectively over the barrier layer in the second trench, and deposited over the work function layer in the first trench. The precursor selectively reacts with the barrier layer to selectively etch the barrier layer, and selectively reacts with the work function layer to selectively etch a top oxidized portion of the work function layer and deposit a protective layer. The reaction products between the precursor and the barrier layer, and the reaction products between the precursor and the work function layer are removed by using an inert gas.