An embodiment method includes: forming a dielectric-containing substrate over a semiconductor substrate; forming a stack of first semiconductor layers and second semiconductor layers over the dielectric-containing substrate, wherein the first semiconductor layers and the second semiconductor layers have different material compositions and alternate with one another within the stack; patterning the first semiconductor layer and the second semiconductor layers into a fin structure such that the fin structure includes sacrificial layers including the second semiconductor layers and channel layers including the first semiconductor layers; forming source/drain features adjacent to the sacrificial layers and the channel layers; removing the sacrificial layers of the fin structure so that the channel layers of the fin structure are exposed; and forming a gate structure around the exposed channel layers, wherein the dielectric-containing substrate is interposed between the gate structure and the semiconductor substrate.

A semiconductor device with different configurations of gate structures and a method of fabricating the semiconductor device are disclosed. The semiconductor device includes first and second gate structures disposed on first and second nanostructured channel regions, respectively. The first gate structure includes a nWFM layer disposed on the first nanostructured channel region, a barrier layer disposed on the nWFM layer, a first pWFM layer disposed on the barrier layer, and a first gate fill layer disposed on the first pWFM layer. Sidewalls of the first gate fill layer are in physical contact with the barrier layer. The second gate structure includes a gate dielectric layer disposed on the second nanostructured channel region, a second pWFM layer disposed on the gate dielectric layer, and a second gate fill layer disposed on the pWFM layer. Sidewalls of the second gate fill layer are in physical contact with the gate dielectric layer.

A method of independently forming source/drain regions in NMOS regions including nanosheet field-effect transistors (NSFETs), NMOS regions including fin field-effect transistors (FinFETs) PMOS regions including NSFETs, and PMOS regions including FinFETs and semiconductor devices formed by the method are disclosed. In an embodiment, a device includes a semiconductor substrate; a first nanostructure over the semiconductor substrate; a first epitaxial source/drain region adjacent the first nanostructure; a first inner spacer layer adjacent the first epitaxial source/drain region, the first inner spacer layer comprising a first material; a second nanostructure over the semiconductor substrate; a second epitaxial source/drain region adjacent the second nanostructure; and a second inner spacer layer adjacent the second epitaxial source/drain region, the second inner spacer layer comprising a second material different from the first material.

A semiconductor device includes a substrate, a first source/drain feature and a second source/drain feature over the substrate, a first semiconductor layer and a second semiconductor layer between the first and the second source/drain features, and a gate between the first and the second source/drain features. A portion of the gate is further between the first and the second semiconductor layers. Moreover, the semiconductor device includes a first inner spacer and a second inner spacer. The first inner spacer is between the first and the second semiconductor layers and further between the portion of the gate and a portion of the first source/drain feature. Furthermore, the portion of the first source/drain feature is between the first semiconductor layer and the second semiconductor layer. The first inner spacer has a U-shaped profile. Additionally, the second inner spacer is between the first inner spacer and the portion of the first source/drain feature.

Approaches herein provide devices and methods for forming optimized gate-all-around transistors. One method may include forming a plurality of nanosheets each comprising a plurality of alternating first layers and second layers, and etching the plurality of nanosheets to laterally recess the second layers relative to the first layers. The method may further include forming an inner spacer over the recessed second layers by forming a spacer material along an exposed portion of each of the plurality of nanosheets, etching the spacer material to remove the spacer material from the first layers of each of the plurality of nanosheets, and performing a sidewall treatment to the plurality of nanosheets after the spacer material is removed from the first layers of each of the plurality of nanosheets.

Integrated circuit structures having gate cut offset, and methods of fabricating integrated circuit structures having gate cut offset, are described. For example, an integrated circuit structure includes a first vertical stack of horizontal nanowires. A second vertical stack of horizontal nanowires is spaced apart from and parallel with the first vertical stack of horizontal nanowires. A gate structure includes a first gate structure portion over the first vertical stack of horizontal nanowires, a second gate structure over the second vertical stack of horizontal nanowires, and a gate cut between the first gate structure portion and the second gate structure portion, the gate cut laterally closer to the second vertical stack of horizontal nanowires than to the first vertical stack of horizontal nanowires.

A semiconductor device structure is provided. The semiconductor device structure includes a substrate having a base, a first fin, and a second fin over the base. The semiconductor device structure includes a first nanostructure and a second nanostructure over the first fin and the second fin respectively. The semiconductor device structure includes an isolation structure between the first fin and the second fin and between the first nanostructure and the second nanostructure. The isolation structure has an air gap. The isolation structure over the air gap has a first portion and a second portion, and there is a boundary between the first portion and the second portion. The semiconductor device structure includes an isolation layer over the base. The semiconductor device structure includes a first gate stack over the isolation layer and wrapped around the first nanostructure.

A semiconductor device structure is provided. The semiconductor device structure includes a substrate having a base. The semiconductor device structure includes a first multilayer stack over the base. The first multilayer stack includes a first channel layer and a second channel layer over and spaced apart from the first channel layer. The semiconductor device structure includes a gate stack over the substrate. The gate stack wraps around the first multilayer stack. The semiconductor device structure includes an inner spacer layer between the second channel layer and the first channel layer and between the first channel layer and the base. The semiconductor device structure includes a bottom spacer over the base. The semiconductor device structure includes a first source/drain structure over the bottom spacer and connected to the second channel layer.

A device includes a first gate region having a first gate length; a first spacer on a sidewall of the first gate region; a semiconductor layer over the first gate region; a second gate region over the semiconductor layer, wherein the second gate region has a second gate length equal to the first gate length; and a second spacer on a sidewall of second gate region, wherein the second spacer is wider than the first spacer.

Gate-all-around integrated circuit structures having vertically discrete source or drain structures, and methods of fabricating gate-all-around integrated circuit structures having vertically discrete source or drain structures, are described. For example, an integrated circuit structure includes a vertical arrangement of horizontal nanowires. A gate stack is around the vertical arrangement of horizontal nanowires. A first epitaxial source or drain structure is at a first end of the vertical arrangement of horizontal nanowires, the first epitaxial source or drain structure including vertically discrete portions aligned with the vertical arrangement of horizontal nanowires. A second epitaxial source or drain structure is at a first end of the vertical arrangement of horizontal nanowires, the second epitaxial source or drain structure including vertically discrete portions aligned with the vertical arrangement of horizontal nanowires.