Abstract: A semiconductor device includes a plurality of semiconductor layers arranged one above another, and source/drain epitaxial regions on opposite sides of the plurality of semiconductor layers. The semiconductor device further includes a gate structure surrounding each of the plurality of semiconductor layers. The gate structure includes interfacial layers respectively over the plurality of semiconductor layers, a high-k dielectric layer over the interfacial layers, and a gate metal over the high-k dielectric layer. The gate structure further includes gate spacers spacing apart the gate structure from the source/drain epitaxial regions. A top position of the high-k dielectric layer is lower than top positions of the gate spacers.

Abstract: A semiconductor device includes source and a drain above a substrate and spaced apart along a first direction, and a semiconductor channel extending between the source and the drain. The semiconductor device further includes gate spacers, an interfacial layer, and a metal gate structure. The gate spacers are disposed on the semiconductor channel and spaced apart by a spacer-to-spacer distance along the first direction. The interfacial layer is on the semiconductor channel. The interfacial layer extends a length along the first direction, and the length is less than a minimum of the spacer-to-spacer distance along the first direction. The metal gate structure is over the interfacial layer.

Abstract: A semiconductor device includes source and a drain above a substrate and spaced apart along a first direction, and a semiconductor channel extending between the source and the drain. The semiconductor device further includes gate spacers, an interfacial layer, and a metal gate structure. The gate spacers are disposed on the semiconductor channel and spaced apart by a spacer-to-spacer distance along the first direction. The interfacial layer is on the semiconductor channel. The interfacial layer extends a length along the first direction, and the length is less than a minimum of the spacer-to-spacer distance along the first direction. The metal gate structure is over the interfacial layer.

Abstract: A method of manufacturing a semiconductor device includes forming a fin structure comprising alternately stacked first semiconductor layers and second semiconductor layers over a substrate. A sacrificial gate structure is formed over the fin structure. Spacers are formed on either side of the sacrificial gate structure. The sacrificial gate structure is removed to form a trench between the spacers. The first semiconductor layers are removed from the trench, while leaving the second semiconductor layers suspended in the trench. A self-assembling monolayer is formed on sidewalls of the spacers in the trench. Interfacial layers are formed encircling the suspended second semiconductor layers, respectively. A high-k dielectric layer is deposited at a faster deposition rate on the interfacial layers than on the self-assembling monolayer. A metal gate structure is formed over the high-k dielectric layer.

Abstract: A method of manufacturing a semiconductor device includes forming a fin structure comprising alternately stacked first semiconductor layers and second semiconductor layers over a substrate. A sacrificial gate structure is formed over the fin structure. Spacers are formed on either side of the sacrificial gate structure. The sacrificial gate structure is removed to form a trench between the spacers. The first semiconductor layers are removed from the trench, while leaving the second semiconductor layers suspended in the trench. A self-assembling monolayer is formed on sidewalls of the spacers in the trench. Interfacial layers are formed encircling the suspended second semiconductor layers, respectively. A high-k dielectric layer is deposited at a faster deposition rate on the interfacial layers than on the self-assembling monolayer. A metal gate structure is formed over the high-k dielectric layer.