A method includes forming a dummy gate stack over a semiconductor region, forming a source/drain region on a side of the dummy gate stack, removing the dummy gate stack to form a trench, depositing a gate dielectric layer extending into the trench, depositing a metal-containing layer over the gate dielectric layer, and depositing a silicon-containing layer on the metal-containing layer. The metal-containing layer and the silicon-containing layer in combination act as a work-function layer. A planarization process is performed to remove excess portions of the silicon-containing layer, the metal-containing layer, and the gate dielectric layer, with remaining portions of the silicon-containing layer, the silicon-containing layer, and the gate dielectric layer forming a gate stack.

A method includes forming a dummy gate stack over a semiconductor region, forming epitaxial source/drain regions on opposite sides of the dummy gate stack, removing the dummy gate stack to form a trench, depositing a gate dielectric layer extending into the trench, and depositing a work-function layer over the gate dielectric layer. The work-function layer comprises a seam therein. A silicon-containing layer is deposited to fill the seam. A planarization process is performed to remove excess portions of the silicon-containing layer, the work-function layer, and the gate dielectric layer. Remaining portions of the silicon-containing layer, the work-function layer, and the gate dielectric layer form a gate stack.

The present disclosure describes a method includes forming a fin structure including a fin bottom portion and a stacked fin portion on a substrate. The stacked fin portion includes a first semiconductor layer and a second semiconductor layer, in which the first semiconductor layer includes germanium. The method further includes etching the fin structure to form an opening, delivering a primary etchant and a germanium-containing gas to the fin structure through the opening, and etching a portion of the second semiconductor layer in the opening with the primary etchant and the germanium-containing gas.

A method of fabricating a semiconductor device is described. A plurality of fins is formed over a substrate. Dummy gates are formed patterned over the fins, each dummy gate having a spacer on sidewalls of the patterned dummy gates. Recesses are formed in the fins using the patterned dummy gates as a mask. A passivation layer is formed over the fins and in the recesses in the fins. The passivation layer is patterned to leave a remaining passivation layer only in some of the recesses in the fins. Source and drain regions are epitaxially formed only in the recesses in the fins without the remaining passivation layer.

A device includes a substrate, a first semiconductor channel over the substrate, a second semiconductor channel over the substrate and laterally offset from the first semiconductor channel, and a third semiconductor channel over the substrate and laterally offset from the second semiconductor channel. A first gate structure, a second gate structure, and a third gate structure are over and lateral surround the first, second, and third semiconductor channels, respectively. A first inactive fin is between the first gate structure and the second gate structure, and a second inactive fin is between the second gate structure and the third gate structure. A bridge conductor layer is over the first, second, and third gate structures, and the first and second inactive fins. A dielectric plug extends from an upper surface of the second inactive fin, through the bridge conductor layer, to at least an upper surface of the bridge conductor layer.

A semiconductor structure includes a semiconductor fin protruding from a substrate; a gate structure engaging with the semiconductor fin. The semiconductor structure also includes an interlayer dielectric (ILD) layer disposed over the substrate and adjacent to the gate structure, where a top surface of the gate structure is below a top surface of the ILD layer; a first metal layer in direct contact with a top surface of the gate structure; a second metal layer disposed over the first metal layer, where the first metal layer is disposed on bottom and sidewall surfaces of the second metal layer, where the bottom surface of the second metal layer has a concave profile, and where the second metal layer differs from the first metal layer in composition; and a gate contact disposed over the second metal layer.

A method includes forming a fin protruding from a substrate, forming a first dielectric feature adjacent to the fin over the substrate, forming a cladding layer over the fin and the first dielectric feature, and removing a portion of the cladding layer to form an opening. The opening exposes the first dielectric feature. The method further includes forming a second dielectric feature adjacent to the cladding layer, the second dielectric feature filling the opening, forming a dummy gate stack over the fin and the second dielectric feature, forming source/drain (S/D) features in the fin adjacent to the dummy gate stack, and replacing the dummy gate stack and the cladding layer with a metal gate stack. The second dielectric feature divides the metal gate stack.

A method of fabricating a device includes providing a fin having a stack of epitaxial layers including a plurality of semiconductor channel layers interposed by a plurality of dummy layers. A source/drain etch process is performed to remove portions of the stack of epitaxial layers in source/drain regions to form trenches that expose lateral surfaces of the stack of epitaxial layers. A dummy layer recess process is performed to laterally etch the plurality of dummy layers to form recesses along sidewalls of the trenches. An inner spacer material is deposited along sidewalls of the trenches and within the recesses. An inner spacer etch-back process is performed to remove the inner spacer material from the sidewalls of the trenches and to remove a portion of the inner spacer material from within the recesses to form inner spacers having a dish-like region along lateral surfaces of the inner spacers.

Semiconductor devices and methods are provided. In an embodiment, a semiconductor device includes first nanostructures directly over a first portion of a substrate and second nanostructures directly over a second portion of the substrate, n-type source/drain features coupled to the first nanostructures and p-type source/drain features coupled to the second nanostructures, and an isolation structure disposed between the first portion of the substrate and the second portion of the substrate. The isolation structure includes a first smiling region in direct contact with the first portion of the substrate and having a first height. The isolation structure also includes a second smiling region in direct contact with the second portion of the substrate and having a second height, the first height is greater than the second height.

A semiconductor device and a method of forming the same are provided. In an embodiment, an exemplary semiconductor device includes a vertical stack of channel members disposed over a substrate, a gate structure wrapping around each channel member of the vertical stack of channel members, and a source/drain feature disposed over the substrate and coupled to the vertical stack of channel members. The source/drain feature is spaced apart from a sidewall of the gate structure by an air gap and a dielectric layer, and the air gap extends into the source/drain feature.