A semiconductor structure may include one or more metal gates, one or more channels below the one or more metal gates, a gate dielectric layer separating the one or more metal gates from the one or more channels, and a high-k material embedded in the gate dielectric layer. Both the high-k material and the gate dielectric layer may be in direct contact with the one or more channels. The high-k material may provide threshold voltage variation in the one or more metal gates. The high-k material is a first high-k material or a second high-k material. The semiconductor structure may only include the first high-k material embedded in the gate dielectric layer. The semiconductor structure may only include the second high-k material embedded in the gate dielectric layer. The semiconductor structure may include both the first high-k material and the second high-k material embedded in the gate dielectric layer.

Devices and structures that include a gate spacer having a gap or void are described along with methods of forming such devices and structures. In accordance with some embodiments, a structure includes a substrate, a gate stack over the substrate, a contact over the substrate, and a spacer disposed laterally between the gate stack and the contact. The spacer includes a first dielectric sidewall portion and a second dielectric sidewall portion. A void is disposed between the first dielectric sidewall portion and the second dielectric sidewall portion.

The present disclosure describes a semiconductor device and methods for forming the same. The semiconductor device includes nanostructures on a substrate and a source/drain region in contact with the nanostructures. The source/drain region includes epitaxial end caps, where each epitaxial end cap is formed at an end portion of a nanostructure of the nanostructures. The source/drain region also includes an epitaxial body in contact with the epitaxial end caps and an epitaxial top cap formed on the epitaxial body. The semiconductor device further includes gate structure formed on the nanostructures.

Semiconductor devices having improved gate electrode structures and methods of forming the same are disclosed. In an embodiment, a semiconductor device includes a gate structure over a semiconductor substrate, the gate structure including a high-k dielectric layer; an n-type work function layer over the high-k dielectric layer; an anti-reaction layer over the n-type work function layer, the anti-reaction layer including a dielectric material; a p-type work function layer over the anti-reaction layer, the p-type work function layer covering top surfaces of the anti-reaction layer; and a conductive cap layer over the p-type work function layer.

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.

Semiconductor device fabrication method is provided. The method includes providing a substrate; forming a first semiconductor layer on the substrate; forming a stack of semiconductor layer structures on the first semiconductor layer, each of the semiconductor layer structures comprising a second semiconductor layer and a third semiconductor layer on the second semiconductor layer, the second and third semiconductor layers having at least a common compound element, and the third semiconductor layer and the first semiconductor layer having a same semiconductor compound; performing an etching process to form a fin structure; performing a selective etching process on the second semiconductor layer to form a first air gap between the first semiconductor layer and the third semiconductor layer and a second air gap between each of adjacent third semiconductor layers in the stack of one or more semiconductor layer structures; and filling the first and second air gaps with an insulator layer.

Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a fin structure over a semiconductor substrate. The semiconductor device structure also includes a gate stack covering a portion of the fin structure. The semiconductor device structure further includes a spacer element over a sidewall of the gate stack. The spacer element includes a first layer and a second layer over the first layer. The dielectric constant of the first layer is greater than the dielectric constant of the second layer. A gate dielectric layer of the gate stack adjoins the first layer and the second layer.

Structures for a bipolar junction transistor and methods of forming a structure for a bipolar junction transistor. The structure includes an emitter having a raised portion, a collector having a raised portion, and a base having a base layer and an extrinsic base layer stacked with the base layer. The base layer and the extrinsic base layer are positioned in a lateral direction between the raised portion of the emitter and the raised portion of the collector, the base layer has a first width in the lateral direction, the extrinsic base layer has a second width in the lateral direction, and the second width is greater than the first width.

A method comprising: forming a substrate; forming a first nanowire over the substrate; forming a second nanowire over the substrate; forming a gate over a portion of the first and second nanowires; implanting a dopant such that a region between the first and second nanowires under the gate does not receive the dopant while a region between the first and second nanowires away from the gate receives the dopant, wherein the dopant amorphize a material of the region between the first and second nanowires away from the gate; and isotopically etching of the region between the first and second nanowires away from the gate.

In accordance with an embodiment of the present invention, a method and semiconductor device is described, including forming a plurality of gaps of variable size between device features, each of the gaps including vertical sidewalls perpendicular to a substrate surface and a horizontal surface parallel to the substrate surface. Spacer material is directionally deposited concurrently on the horizontal surface in each gap and in a flat area using a total flow rate of gaseous precursors that minimizes gap-loading in a smallest gap compared to the flat area such that the spacer material is deposited on the substrate surface in each gap and in the flat area to a uniform thickness.