Abstract: The present disclosure describes a semiconductor device having a channel structure with profile control. The semiconductor device includes a fin structure on a substrate. The fin structure includes a bottom portion on the substrate and a top portion including multiple semiconductor layers. The semiconductor device further includes a gate structure wrapped around the multiple semiconductor layers and a source/drain (S/D) structure on the bottom portion of the fin structure and in contact with the plurality of semiconductor layers. The S/D structure extends into end portions of the multiple semiconductor layers.

Abstract: The present disclosure describes a semiconductor device having a channel structure with profile control. The semiconductor device includes a fin structure on a substrate. The fin structure includes a bottom portion on the substrate and a top portion including multiple semiconductor layers. The semiconductor device further includes a gate structure wrapped around the multiple semiconductor layers and a source/drain (S/D) structure on the bottom portion of the fin structure and in contact with the plurality of semiconductor layers. The S/D structure extends into end portions of the multiple semiconductor layers.

Abstract: Methods and semiconductor structures are provided. A method according to the present disclosure includes depositing a top epitaxial layer over a substrate, forming a fin structure from the top epitaxial layer and a portion of the substrate, recessing a source/drain region of the fin structure to form a source/drain recess, conformally depositing a semiconductor layer over surfaces of the source/drain recess, etching back the semiconductor layer to form a diffusion stop layer over a bottom surface of the source/drain recess, depositing a first epitaxial layer over the diffusion stop layer and sidewalls source/drain recess, depositing a second epitaxial layer over the first epitaxial layer, and depositing a third epitaxial layer over the second epitaxial layer. A germanium concentration of the diffusion stop layer is greater than a germanium concentration of the top epitaxial layer or a germanium concentration of the first epitaxial layer.

Abstract: Methods and semiconductor structures are provided. A method according to the present disclosure includes depositing a top epitaxial layer over a substrate, forming a fin structure from the top epitaxial layer and a portion of the substrate, recessing a source/drain region of the fin structure to form a source/drain recess, conformally depositing a semiconductor layer over surfaces of the source/drain recess, etching back the semiconductor layer to form a diffusion stop layer over a bottom surface of the source/drain recess, depositing a first epitaxial layer over the diffusion stop layer and sidewalls source/drain recess, depositing a second epitaxial layer over the first epitaxial layer, and depositing a third epitaxial layer over the second epitaxial layer. A germanium concentration of the diffusion stop layer is greater than a germanium concentration of the top epitaxial layer or a germanium concentration of the first epitaxial layer.

Abstract: The present disclosure describes a semiconductor device having a channel structure with profile control. The semiconductor device includes a fin structure on a substrate. The fin structure includes a bottom portion on the substrate and a top portion including multiple semiconductor layers. The semiconductor device further includes a gate structure wrapped around the multiple semiconductor layers and a source/drain (S/D) structure on the bottom portion of the fin structure and in contact with the plurality of semiconductor layers. The S/D structure extends into end portions of the multiple semiconductor layers.

Abstract: A semiconductor device includes a semiconductor fin and a gate structure above the semiconductor fin. The semiconductor fin includes a bottom portion and a top portion above the bottom portion. The bottom portion and the top portion are made of different materials. The top portion includes a head part and a neck part between the head part and the bottom portion. The neck part has a width less than a width of the head part, and the neck part is in contact with the bottom portion.

Abstract: A semiconductor device includes a fin structure disposed over a substrate, wherein the fin structure including a channel layer and extending in a first direction, a gate structure including a gate electrode layer and a gate dielectric layer, sidewall spacers disposed on opposite side faces of the gate structure, and a source/drain structure including an epitaxial layer having at least seven facets in a cross section along the first direction.

Abstract: A semiconductor device includes a semiconductor fin and a gate structure above the semiconductor fin. The semiconductor fin includes a bottom portion and a top portion above the bottom portion. The bottom portion and the top portion are made of different materials. The top portion includes a head part and a neck part between the head part and the bottom portion. The neck part has a width less than a width of the head part, and the neck part is in contact with the bottom portion.

Abstract: A semiconductor device includes a fin structure disposed over a substrate, wherein the fin structure including a channel layer and extending in a first direction, a gate structure including a gate electrode layer and a gate dielectric layer, sidewall spacers disposed on opposite side faces of the gate structure, and a source/drain structure including an epitaxial layer having at least seven facets in a cross section along the first direction

Abstract: A semiconductor device includes a fin structure disposed over a substrate, wherein the fin structure including a channel layer and extending in a first direction, a gate structure including a gate electrode layer and a gate dielectric layer, sidewall spacers disposed on opposite side faces of the gate structure, and a source/drain structure including an epitaxial layer having at least seven facets in a cross section along the first direction.

Abstract: A semiconductor device includes a fin structure disposed over a substrate, wherein the fin structure including a channel layer and extending in a first direction, a gate structure including a gate electrode layer and a gate dielectric layer, sidewall spacers disposed on opposite side faces of the gate structure, and a source/drain structure including an epitaxial layer having at least seven facets in a cross section along the first direction