Abstract: Various transistors, such as horizontal gate-all-around transistors, and methods of fabricating such are disclosed herein. An exemplary transistor includes a first nanowire and a second nanowire that include a first semiconductor material, a gate that wraps a channel region of the first nanowire and the second nanowire, and source/drain feature that wraps source/drain regions of the first nanowire and the second nanowire. The source/drain feature includes a second semiconductor material that is configured differently than the first semiconductor material. In some implementations, the transistor further includes a fin-like semiconductor layer disposed over a substrate. The first nanowire and the second nanowire are disposed over the fin-like semiconductor layer, such that the first nanowire, the second nanowire, and the fin-like semiconductor layer extend substantially parallel to one another along the same length-wise direction.

Abstract: A method of fabricating semiconductor devices is provided. The method includes forming a fin protruding from a substrate, and forming a disposable mandrel fin on the fin. The method also includes epitaxially growing channel fins on sidewalls of the disposable mandrel fin. The method further includes removing the disposable mandrel fin to form a space between the channel fins, and forming a gate structure to fill the space between the channel fins and to wrap the channel fins. In addition, the method includes forming source and drain structures on opposite sides of the gate structure.

Abstract: Semiconductor device and the manufacturing method thereof are disclosed herein. An exemplary method comprises forming a fin over a substrate, wherein the fin comprises a first semiconductor layer and a second semiconductor layer including different semiconductor materials, and the fin comprises a channel region and a source/drain region; forming a dummy gate structure over the channel region of the fin and over the substrate; etching a portion of the fin in the source/drain region to form a trench therein, wherein a bottom surface of the trench is below a bottom surface of the second semiconductor layer; selectively removing an edge portion of the second semiconductor layer in the channel region such that the second semiconductor layer is recessed; forming a sacrificial structure around the recessed second semiconductor layer and over the bottom surface of the trench; and epitaxially growing a source/drain feature in the source/drain region of the fin.

Abstract: A semiconductor structure includes a fin disposed on a substrate, the fin including a channel region comprising a plurality of channels vertically stacked over one another, the channels comprising germanium distributed therein. The semiconductor structure further includes a gate stack engaging the channel region of the fin and gate spacers disposed between the gate stack and the source and drain regions of the fin, wherein each channel of the channels includes a middle section wrapped around by the gate stack and two end sections engaged by the gate spacers, wherein a concentration of germanium in the middle section of the channel is higher than a concentration of germanium in the two end sections of the channel, and wherein the middle section of the channel further includes a core portion and an outer portion surrounding the core portion with a germanium concentration profile from the core portion to the outer portion.

Abstract: The present disclosure provides a semiconductor device that includes a semiconductor fin disposed over a substrate; an isolation structure at least partially surrounding the fin; an epitaxial source/drain (S/D) feature disposed over the semiconductor fin, wherein an extended portion of the epitaxial S/D feature extends over the isolation structure; and a silicide layer disposed on the epitaxial S/D feature, the silicide layer continuously surrounding the extended portion of the epitaxial S/D feature over the isolation structure.

Abstract: A method of fabricating semiconductor devices is provided. The method includes forming a fin protruding from a substrate, and forming a disposable mandrel fin on the fin. The method also includes epitaxially growing channel fins on sidewalls of the disposable mandrel fin. The method further includes removing the disposable mandrel fin to form a space between the channel fins, and forming a gate structure to fill the space between the channel fins and to wrap the channel fins. In addition, the method includes forming source and drain structures on opposite sides of the gate structure.

Abstract: Provided are FinFET devices and methods of forming the same. A FinFET device includes a substrate, a first gate strip and a second gate strip. The substrate has at least one first fin in a first region, at least one second fin in a second region and an isolation layer covering lower portions of the first and second fins. The first fin includes a first material layer and a second material layer over the first material layer, and the interface between the first material layer and the second material layer is uneven. The first gate strip is disposed across the first fin. The second gate strip is disposed across the second fin.

Abstract: A method includes forming a first dielectric layer over a semiconductor fin protruding from a substrate, forming a second dielectric layer over the first dielectric layer, then removing a portion of the semiconductor fin to form a first recess defined by portions of the first dielectric layer, followed by removing that portions of the first dielectric layer that define the first recess. Thereafter, the method proceeds to forming an epitaxial source/drain (S/D) feature in the first recess, removing the second dielectric layer to form a second recess that is disposed between the epitaxial S/D feature and remaining portions of the first dielectric layer, and subsequently forming a silicide layer over the epitaxial S/D feature, such that the silicide layer wraps around the epitaxial S/D feature.

Abstract: A method that includes forming first semiconductor layers and second semiconductor layers disposed over a substrate, wherein the first and second semiconductor layers have different material compositions, are alternatingly disposed, and extend over first and second regions of the substrate; patterning the first and the second semiconductor layers to form a first fin in the first region and a second fin in the second region; removing the first semiconductor layers from the first and second fins such that a first portion of the patterned second semiconductor layers becomes first suspended nanostructures in the first fin and that a second portion of the patterned second semiconductor layers becomes second suspended nanostructures in the second fin; forming third semiconductor layers on the second suspended nanostructures in the second fin; and performing an anneal process to drive materials contained in the third semiconductor layers into corresponding second suspended nanostructures in the second fin.

Abstract: A method for forming a semiconductor device structure is provided. The method includes providing a substrate. The method includes forming a first dielectric layer over the base portion and a first sidewall of the fin portion. The method includes forming a first spacer layer over the first dielectric layer. The method includes forming a first dielectric fin over the first spacer layer. The method includes forming an epitaxial structure over the fin portion, wherein a void is surrounded by the epitaxial structure, the first dielectric layer, and the first spacer layer. The method includes removing the first spacer layer between the epitaxial structure and the first dielectric fin. The method includes forming a silicide layer over the epitaxial structure, wherein a first lower portion of the silicide layer covers a lower surface of the epitaxial structure and is in the void.

Abstract: Methods of fabricating semiconductor devices are provided. The method includes forming a gate structure over a substrate, forming a disposable spacer on a sidewall of the gate structure, and forming a source region and a drain region at opposite sides of the gate structure. The method also includes depositing an interlayer dielectric layer around the disposable spacer, and forming a first hard mask on the interlayer dielectric layer. The method further includes removing an upper portion of the gate structure, and removing the disposable spacer to form a trench between the gate structure and the interlayer dielectric layer. In addition, the method includes sealing the trench to form an air-gap spacer, and forming a second hard mask on the gate structure.

Abstract: A semiconductor device and methods of forming the same are disclosed. The semiconductor device includes a substrate, first and second source/drain (S/D) regions, a channel between the first and second S/D regions, a gate engaging the channel, and a contact feature connecting to the first S/D region. The contact feature includes first and second contact layers. The first contact layer has a conformal cross-sectional profile and is in contact with the first S/D region on at least two sides thereof. In embodiments, the first contact layer is in direct contact with three or four sides of the first S/D region so as to increase the contact area. The first contact layer includes one of a semiconductor-metal alloy, an III-V semiconductor, and germanium.

Abstract: A semiconductor device having a first region and a second region is provided. The first region has a first protruding structure and a second protruding structure. The second region has a third protruding structure and a fourth protruding structure. First, second, third, and fourth epi-layers are formed on the first, second, third, and fourth protruding structures, respectively. The first and second epi-layers are covered with a first photoresist layer while leaving the third and fourth epi-layers exposed. A dielectric layer is formed over the first photoresist layer and over the third and fourth epi-layers. A portion of the dielectric layer is covered with a second photoresist layer. The portion of the dielectric layer is formed over the third and fourth epi-layers. Portions of the dielectric layer not protected by the first and second photoresist layers are etched. The first and second photoresist layers are removed.

Abstract: The present disclosure provides a method of semiconductor fabrication that includes forming a semiconductor fin protruding from a substrate, the semiconductor fin including a plurality of first semiconductor layers of a first semiconductor material and second semiconductor layers of a second semiconductor material alternatively stacked, the second semiconductor material being different from the first semiconductor material in composition; forming a first gate stack on the semiconductor fin; forming a recess in the semiconductor fin within a source/drain (S/D) region adjacent to the first gate stack, a sidewall of the first and second semiconductor material layers being exposed within the recess; performing an etching process to the semiconductor fin, resulting in an undercut below the first gate stack; epitaxially growing on the sidewall of the semiconductor fin to fill in the undercut with a semiconductor extended feature of the first semiconductor material; and growing an epitaxial S/D feature from the rece

Abstract: A device structure includes: a core structure formed on a support, and a shell material formed on the core structure and surrounding at least part of the core structure. The shell material is associated with a first bandgap; the core structure is associated with a second bandgap; and the first bandgap is smaller than the second bandgap. The shell material and the core structure are configured to form a quantum-well channel in the shell material.

Abstract: In a method for manufacturing a semiconductor device, a gate structure is formed over a channel layer and an isolation insulating layer. A first sidewall spacer layer is formed on a side surface of the gate structure. A sacrificial layer is formed so that an upper portion of the gate structure with the first sidewall spacer layer is exposed from the sacrificial layer and a bottom portion of the gate structure with the first sidewall spacer layer is embedded in the first sacrificial layer. A space is formed between the bottom portion of the gate structure and the sacrificial layer by removing at least part of the first sidewall spacer layer. After the first sidewall spacer layer is removed, an air gap is formed between the bottom portion of the gate structure and the sacrificial layer by forming a second sidewall spacer layer over the gate structure.

Abstract: In a method for manufacturing a semiconductor device, a gate structure is formed over a channel layer and an isolation insulating layer. A first sidewall spacer layer is formed on a side surface of the gate structure. A sacrificial layer is formed so that an upper portion of the gate structure with the first sidewall spacer layer is exposed from the sacrificial layer and a bottom portion of the gate structure with the first sidewall spacer layer is embedded in the first sacrificial layer. A space is formed between the bottom portion of the gate structure and the sacrificial layer by removing at least part of the first sidewall spacer layer. After the first sidewall spacer layer is removed, an air gap is formed between the bottom portion of the gate structure and the sacrificial layer by forming a second sidewall spacer layer over the gate structure.

Abstract: A method for forming a semiconductor device structure is provided. The method includes providing a semiconductor substrate, a gate structure, a first doped structure, a second doped structure, and a dielectric layer. The method includes forming a through hole in the dielectric layer. The method includes performing a physical vapor deposition process to deposit a first metal layer over the first doped structure exposed by the through hole. The method includes reacting the first metal layer with the first doped structure to form a metal semiconductor compound layer between the first metal layer and the first doped structure. The method includes removing the first metal layer. The method includes performing a chemical vapor deposition process to deposit a second metal layer in the through hole. The method includes forming a conductive structure in the through hole and over the second metal layer.

Abstract: A method includes forming a gate stack over a semiconductor region, and forming a first gate spacer on a sidewall of the gate stack. The first gate spacer includes an inner sidewall spacer, and a dummy spacer portion on an outer side of the inner sidewall spacer. The method further includes removing the dummy spacer portion to form a trench, and forming a dielectric layer to seal a portion of the trench as an air gap. The air gap and the inner sidewall spacer in combination form a second gate spacer. A source/drain region is formed to have a portion on an outer side of the second gate spacer.

Abstract: In a method for manufacturing a semiconductor device, a gate structure is formed over a channel layer and an isolation insulating layer. A first sidewall spacer layer is formed on a side surface of the gate structure. A sacrificial layer is formed so that an upper portion of the gate structure with the first sidewall spacer layer is exposed from the sacrificial layer and a bottom portion of the gate structure with the first sidewall spacer layer is embedded in the first sacrificial layer. A space is formed between the bottom portion of the gate structure and the sacrificial layer by removing at least part of the first sidewall spacer layer. After the first sidewall spacer layer is removed, an air gap is formed between the bottom portion of the gate structure and the sacrificial layer by forming a second sidewall spacer layer over the gate structure.