A semiconductor device including a FET includes an isolation insulating layer disposed in a trench of the substrate, a gate dielectric layer disposed over a channel region of the substrate, a gate electrode disposed over the gate dielectric layer, a source and a drain disposed adjacent to the channel region, and an embedded insulating layer disposed below the source, the drain and the gate electrode and both ends of the embedded insulating layer are connected to the isolation insulating layer.

A semiconductor device including a substrate including a division region extending in a first direction, first and second active patterns on the substrate with the division region interposed therebetween, the first and the second active patterns being spaced apart from each other in a second direction perpendicular to the first direction, gate electrodes extending in the first direction and crossing the first and second active patterns, a first channel pattern on the first active pattern, and a second channel pattern on the second active pattern may be provided. The smallest width of the first active pattern may be smaller than the smallest width of the second active pattern, in the first direction. An end portion of the first channel pattern adjacent to the division region may include a protruding portion extending in the first direction, and the protruding portion may have a triangle shape in a plan view.

A semiconductor device includes: a substrate, an active pattern extending in a first horizontal direction on the substrate, a plurality of nanosheets spaced apart from each other and stacked in a vertical direction on the active pattern, a gate electrode extending in a second horizontal direction different from the first horizontal direction on the active pattern, the gate electrode surrounding the plurality of nanosheets, a source/drain region disposed on at least one side of the gate electrode on the active pattern, the source/drain region including a first layer doped with a metal, and a second layer disposed on the first layer, and an inner spacer disposed between the gate electrode and the first layer, between each of the plurality of nanosheets, the inner spacer in contact with the first layer, the inner spacer including a metal oxide formed by oxidizing the same material as the metal.

A semiconductor device includes: a substrate; a fin protruding above the substrate; a gate structure over the fin; source/drain regions over the fin and on opposing sides of the gate structure; channel layers over the fin and between the source/drain regions, where the gate structure wraps around the channel layers; and isolation structures under the source/drain regions, where the isolation structures separate the source/drain regions from the fin, where each of the isolation structures includes a liner layer and a dielectric layer over the liner layer, where the dielectric layer has a plurality of sublayers.

A method for manufacturing a semiconductor structure includes: forming a channel portion on a fin portion; forming two source/drain portions on the fin portion and at two opposite sides of the channel portion, in which each of the two source/drain portions includes a first semiconductor material that is doped with dopant impurities; and forming two bottom portions each of which is disposed between the fin portion and a corresponding one of the two source/drain portions, in which each of the two bottom portions includes a second semiconductor material that is different from the first semiconductor material and that is capable of trapping the dopant impurities when the dopant impurities in the first semiconductor material diffuse toward the fin portion.

A method includes forming a stack of layers, which includes a plurality of semiconductor nanostructures, and a plurality of sacrificial layers. The plurality of semiconductor nanostructures and the plurality of sacrificial layers are arranged alternatingly. The method further includes laterally recessing the plurality of sacrificial layers to form lateral recesses, depositing a spacer layer extending into the lateral recesses, trimming the spacer layer to form inner spacers, and performing a treatment process to reduce dielectric constant values of the inner spacers.

A semiconductor structure includes a substrate, a vertical stack including nanostructures, and a gate structure wrapping around each of the nanostructures. The nanostructures are suspended and vertically arranged over the substrate. The gate structure includes a gate dielectric layer and a gate electrode formed on the gate dielectric layer. The semiconductor structure further includes inner spacers and gate spacers. The inner spacers are formed on opposite sides of the gate structure, between the nanostructures, and separating the nanostructures from each other. The gate spacers are formed on the opposite sides of the gate structure and over a topmost one of the nanostructures. The gate dielectric layer includes a first portion formed on the nanostructures and a second portion extending from the first portion. The first portion and the second portion have a first thickness and a second thickness, respectively. The first thickness is greater than the second thickness.

A method of manufacturing a semiconductor device includes forming a fin structure in which first semiconductor layers and second semiconductor layers are alternatively stacked, the first and second semiconductor layers having different material compositions; forming a sacrificial gate structure over the fin structure; forming a gate spacer on sidewalls of the sacrificial gate structure; etching a source/drain (S/D) region of the fin structure, which is not covered by the sacrificial gate structure and the gate spacer, thereby forming an S/D trench; laterally etching the first semiconductor layers through the S/D trench, thereby forming recesses; selectively depositing an insulating layer on surfaces of the first and second semiconductor layers exposed in the recesses and the S/D trench, but not on sidewalls of the gate spacer; and growing an S/D epitaxial feature in the S/D trench, thereby trapping air gaps in the recesses.

A method includes forming a gate stack, growing a source/drain region on a side of the gate stack through epitaxy, depositing a contact etch stop layer (CESL) over the source/drain region, depositing an inter-layer dielectric over the CESL, etching the inter-layer dielectric and the CESL to form a contact opening, and etching the source/drain region so that the contact opening extends into the source/drain region. The method further includes depositing a metal layer extending into the contact opening. Horizontal portions, vertical portions, and corner portions of the metal layer have a substantially uniform thickness. An annealing process is performed to react the metal layer with the source/drain region to form a source/drain silicide region. The contact opening is filled to form a source/drain contact plug.

A method includes forming a stack of channel layers and sacrificial layers on a substrate. The channel layers and the sacrificial layers have different material compositions and being alternatingly disposed in a vertical direction. The method further includes patterning the stack to form a semiconductor fin, forming an isolation feature on sidewalls of the semiconductor fin, recessing the semiconductor fin, thereby forming a source/drain recess, such that a recessed top surface of the semiconductor fin is below a top surface of the isolation feature, growing a base epitaxial layer from the recessed top surface of the semiconductor fin, depositing an insulation layer in the source/drain recess, and forming an epitaxial feature in the source/drain recess, wherein the epitaxial feature is above the insulation layer. The insulation layer is above the base epitaxial layer and above a bottommost channel layer.