A multi-stack semiconductor device includes: a lower-stack transistor structure including a lower active region and a lower gate structure, the lower active region including a lower channel structure, and the lower gate structure surrounding the lower channel structure; an upper-stack transistor structure vertically stacked above the lower-stack transistor structure, and including an upper active region and an upper gate structure, the upper active region including an upper channel structure, and the upper gate structure surrounding the upper channel structure; and at least one gate contact plug contacting a top surface of the lower gate structure, wherein the lower gate structure and the upper gate structure have a substantially same size in a plan view, and wherein the lower gate structure is not entirely overlapped by the upper gate structure in a vertical direction.

A transistor device and a method for forming a transistor device are disclosed. The transistor device includes: a SiC semiconductor body that includes a first semiconductor layer and a second semiconductor layer formed on top of the first semiconductor; a trench structure extending from a first surface of the semiconductor body through the second semiconductor layer into the first semiconductor layer; a drain region arranged in the first semiconductor layer; and a plurality of transistor cells each coupled between the drain region and a source node. The trench structure subdivides the second semiconductor layer into a plurality of mesa regions and includes at least one cavity. At least one of the plurality of transistor cells is at least partially integrated in each of the mesa regions.

Semiconductor structures and methods are provided. An exemplary method according to the present disclosure includes receiving a fin-shaped structure comprising a first channel region and a second channel region, a first and a second dummy gate structures disposed over the first and the second channel regions, respectively. The method also includes removing a portion of the first dummy gate structure, a portion of the first channel region and a portion of the substrate under the first dummy gate structure to form a trench, forming a hybrid dielectric feature in the trench, removing a portion of the hybrid dielectric feature to form an air gap, sealing the air gap, and replacing the second dummy gate structure with a gate stack after sealing the air gap.

A method of forming a semiconductor device is provided. The method includes providing a substrate having a first region and a second region; forming a plurality of trenches in the first region of the substrate; forming a multi-layer stack over the substrate and in the trenches; and patterning the multi-layer stack and the substrate to form first nanostructures over first fins in the first region and second nanostructures over second fins in the second region, where the multi-layer stack includes at least one of first semiconductor layers and at least one of second semiconductor layer stacked alternately, and the plurality of trenches are in corresponding ones of the first fins.

A semiconductor structure includes a fin extending from a substrate and oriented lengthwise in a first direction, where the fin includes a stack of semiconductor layers, an isolation feature disposed over the substrate and oriented lengthwise in a second direction perpendicular to the first direction, where the isolation feature is disposed adjacent to the fin, and a metal gate structure having a top portion disposed over the stack of semiconductor layers and a bottom portion interleaved with the stack of semiconductor layers. Furthermore, a sidewall of the bottom portion of the metal gate structure is defined by a sidewall of the isolation feature, and the top portion of the metal gate structure laterally extends over a top surface of the isolation feature.

Semiconductor structures and methods for manufacturing the same are provided. The semiconductor structure includes a substrate and first nanostructures and second nanostructures formed over the substrate. The semiconductor structure also includes a gate structure including a first portion wrapping around the first nanostructures and a second portion wrapping around the second nanostructures. The semiconductor structure also includes a dielectric feature sandwiched between the first portion and the second portion of the gate structure. In addition, the dielectric feature includes a bottom portion and a top portion over the bottom portion, and the top portion of the dielectric feature includes a shell layer and a core portion surrounded by the shell layer.

A semiconductor structure is provided. The semiconductor structure includes a first nanostructure stacked over and spaced apart from a second nanostructure, a gate stack wrapping around the first nanostructure and the second nanostructure, a source/drain feature adjoining the first nanostructure and the second nanostructure, and a first inner spacer layer interposing the gate stack and the source/drain feature and interposing the first nanostructure and the second nanostructure. A dopant in the source/drain feature has a first concentration at an interface between the first inner spacer layer and the source/drain feature and a second concentration at a first distance away from the interface. The first concentration is higher than the second concentration.

An integrated circuit (IC) device includes a fin-type active region on a substrate. A mesa-type channel region protrudes from the fin-type active region in a vertical direction. The mesa-type channel region is integrally connected with the fin-type active region. A gate line substantially surrounds a mesa-type channel region on the fin-type active region. A gate dielectric film is between the mesa-type channel region and the gate line. The mesa-type channel region includes: a plurality of round convex portions, which are convex toward the gate line; a concavo-convex sidewall, which includes a portion of each of the plurality of round convex portions and faces the gate line; and at least one void, which is inside the mesa-type channel region.

The integrated circuit (IC) structure includes a semiconductor substrate, a first active region, a dummy fill region, a second active region, first metal gate structures, and second metal gate structures. The first active region is on the semiconductor substrate. The dummy fill region is on the semiconductor substrate. The second active region is on the semiconductor substrate and spaced apart from the first active region by the dummy fill region. The first metal gate structures extend in the first active region and have a first gate pitch and a first gate width. The second metal gate structures extend in the second active region and have a second gate width greater than the first gate width and a second gate pitch being an integer times the first gate pitch, and the integer being two or more.

A semiconductor device includes a semiconductor film and a gate structure on the semiconductor film. The gate structure includes a multi-stepped gate dielectric on the semiconductor film and a gate electrode on the multi-stepped gate dielectric. The multi-stepped gate dielectric includes a first gate dielectric segment having a first thickness and a second gate dielectric segment having a second thickness that is less than the first thickness.