The present disclosure describes a semiconductor device that includes nanostructures on a substrate and a source/drain region in contact with the nanostructures. The source/drain region includes (i) a first epitaxial structure embedded in the substrate; (ii) a nitride layer on the first epitaxial structure; and a second epitaxial structure on the first epitaxial structure. The semiconductor device also includes a gate structure formed on the nanostructures.

A semiconductor device includes active regions extending in a first direction on a substrate; a gate electrode intersecting the active regions on the substrate, extending in a second direction, and including a contact region protruding upwardly; and an interconnection line on the gate electrode and connected to the contact region, wherein the contact region includes a lower region having a first width in the second direction and an upper region located on the lower region and having a second width smaller than the first width in the second direction, and wherein at least one side surface of the contact region in the second direction has a point at which an inclination or a curvature is changed between the lower region and the upper region.

A semiconductor structure includes a first stack of semiconductor layers disposed over a semiconductor substrate, where the first stack of semiconductor layers includes a first SiGe layer and a plurality of Si layers disposed over the first SiGe layer and the Si layers are substantially free of Ge, and a second stack of semiconductor layers disposed adjacent to the first stack of semiconductor layers, where the second stack of semiconductor layers includes the first SiGe layer and a plurality of second SiGe layers disposed over the first SiGe layer, and where the first SiGe layer and the second SiGe layers have different compositions. The semiconductor structure further includes a first metal gate stack interleaved with the first stack of semiconductor layers to form a first device and a second metal gate stack interleaved with the second stack of semiconductor layers to form a second device different from the first device.

In an embodiment, a device includes: a first nanostructure over a substrate, the first nanostructure including a channel region and a first lightly doped source/drain (LDD) region, the first LDD region adjacent the channel region; a first epitaxial source/drain region wrapped around four sides of the first LDD region; an interlayer dielectric (ILD) layer over the first epitaxial source/drain region; a source/drain contact extending through the ILD layer, the source/drain contact wrapped around four sides of the first epitaxial source/drain region; and a gate stack adjacent the source/drain contact and the first epitaxial source/drain region, the gate stack wrapped around four sides of the channel region.

A method comprises forming a gate structure between gate spacers; etching back the gate structure to fall below top ends of the gate spacers; forming a gate dielectric cap over the etched back gate structure; performing an ion implantation process to form a doped region in the gate dielectric cap; depositing a contact etch stop layer over the gate dielectric cap and an ILD layer over the contact etch stop layer; performing a first etching process to form a gate contact opening extending through the ILD layer and terminating prior to reaching the doped region of the gate dielectric cap; performing a second etching process to deepen the gate contact opening, wherein the second etching process etches the doped region of the gate dielectric cap at a slower etch rate than etching the contact etch stop layer; and forming a gate contact in the deepened gate contact opening.

In a method of manufacturing a semiconductor device, a fin structure, in which first semiconductor layers and second semiconductor layers are alternately stacked, is formed over a bottom fin structure. A sacrificial gate structure having sidewall spacers is formed over the fin structure. A source/drain region of the fin structure, which is not covered by the sacrificial gate structure, is removed. The second semiconductor layers are laterally recessed. Dielectric inner spacers are formed on lateral ends of the recessed second semiconductor layers. The first semiconductor layers are laterally recessed. A source/drain epitaxial layer is formed to contact lateral ends of the recessed first semiconductor layer. The second semiconductor layers are removed thereby releasing the first semiconductor layers in a channel region. A gate structure is formed around the first semiconductor layers.

A semiconductor device and a method of manufacturing the same are disclosed. The semiconductor device includes semiconductor wires disposed over a substrate, a source/drain epitaxial layer in contact with the semiconductor wires, a gate dielectric layer disposed on and wrapping around each channel region of the semiconductor wires, a gate electrode layer disposed on the gate dielectric layer and wrapping around the each channel region, and dielectric spacers disposed in recesses formed toward the source/drain epitaxial layer.

A semiconductor device structure, along with methods of forming such, are described. The structure includes a plurality of semiconductor layers and a first source/drain epitaxial feature in contact with the plurality of semiconductor layers. The first source/drain epitaxial feature includes a bottom portion having substantially straight sidewalls. The structure further includes a spacer having a gate spacer portion and one or more source/drain spacer portions. Each source/drain spacer portion has a first height, and a source/drain spacer portion of the one or more source/drain spacer portions is in contact with one of the substantially straight sidewalls of the first source/drain epitaxial feature. The structure further includes a dielectric feature disposed adjacent one source/drain spacer portion of the one or more source/drain spacer portion. The dielectric has a second height substantially greater than the first height.

A semiconductor device structure, along with methods of forming such, are described. The semiconductor device structure includes a first source/drain epitaxial feature disposed in an NMOS region, a second source/drain epitaxial feature disposed in the NMOS region, a first dielectric feature disposed between the first source/drain epitaxial feature and the second source/drain epitaxial feature, a third source/drain epitaxial feature disposed in a PMOS region, a second dielectric feature disposed between the second source/drain epitaxial feature and the third source/drain epitaxial feature, and a conductive feature disposed over the first, second, and third source/drain epitaxial features and the first and second dielectric features.

Gate-all-around integrated circuit structures having depopulated channel structures, and methods of fabricating gate-all-around integrated circuit structures having depopulated channel structures, are described. For example, an integrated circuit structure includes a first vertical arrangement of nanowires and a second vertical arrangement of nanowires above a substrate, the first vertical arrangement of nanowires having a greater number of active nanowires than the second vertical arrangement of nanowires, and the first and second vertical arrangements of nanowires having co-planar uppermost nanowires. The integrated circuit structure also includes a first vertical arrangement of nanoribbons and a second vertical arrangement of nanoribbons above the substrate, the first vertical arrangement of nanoribbons having a greater number of active nanoribbons than the second vertical arrangement of nanoribbons, and the first and second vertical arrangements of nanoribbons having co-planar uppermost nanoribbons.