A semiconductor device and fabrication method are described for integrating I/O and core nanosheet transistors in a single nanosheet process flow by processing a stack of alternating first and second semiconductor structures formed on a substrate, where the first semiconductor structures located over a I/O thick oxide transistor region include a planar semiconductor channel layer sandwiched between upper and lower dielectric layers, and where the alternating first and second semiconductor structures are processed to form gate-all-around electrodes in a core transistor stack that are connected over a relatively thinner gate dielectric layer to control one or more first planar semiconductor channel layers in the core transistor stack, and to form gate-all-around electrodes in an I/O transistor stack that are connected over a relatively thicker gate dielectric layer to control one or more second planar semiconductor channel layers in the I/O transistor stack.

A method of forming a portion of a gate-all-around field-effect transistor (GAA FET) nanosheet structure includes performing a surface modification process to passivate an exposed surface of a gate spacer formed over a fin-shaped column and exposed surfaces of nanosheet channels, the fin-shaped column comprising a stack of the nanosheet channels and sacrificial layers, and performing a selective deposition process to deposit low-k dielectric material on exposed surfaces of the sacrificial layers, wherein the surface modification process comprises a radical-based plasma process, and the selective deposition process is a plasma enhanced chemical vapor deposition (PECVD) process.

Semiconductor structures and a method of forming the same are provided. In an embodiment, an exemplary semiconductor structure includes a doped region in a substrate and comprising a first-type dopant, a plurality of nanostructures disposed directly over the doped region, a gate structure wrapping around each nanostructure of the plurality of nanostructures, a first epitaxial feature and a second epitaxial feature coupled to the plurality of nanostructures, wherein each of the first epitaxial feature and the second epitaxial feature comprises the first-type dopant, a first insulation feature disposed between the first epitaxial feature and the doped region, and a second insulation feature disposed between the second epitaxial feature and the doped region.

The present disclosure provides a semiconductor device and a method of forming the same. A method according one embodiment of the present disclosure includes forming a stack of channel layers interleaved by sacrificial layers, patterning the stack to form a fin-shape structure, forming a dummy gate stack over a channel region of the fin-shape structure, recessing a source/drain region to form a source/drain trench, forming an epitaxial feature in the source/drain trench, after the forming of the epitaxial feature removing the dummy gate stack, releasing the channel layers in the channel region as channel members, forming a gate structure wrapping around each of the channel members, and after the forming of the gate structure performing an ion implantation to increase a dopant concentration of a dopant in the epitaxial feature.

The present disclosure provides a semiconductor device and a method of forming the same. The semiconductor device includes a fin-shape base protruding from a semiconductor substrate. A top surface of the semiconductor substrate is in a (100) crystal plane, and a top surface of the fin-shape base is in a (110) crystal plane. The semiconductor device also includes channel members disposed over the top surface of the fin-shape base, a gate structure wrapping around at least one of channel members, a gate spacer extending along a sidewall of the gate structure, a source/drain feature abutting the channel members, and a dopant-free epitaxial feature under the source/drain feature. A top surface of the source/drain feature is in a (110) crystal plane. A top surface of the dopant-free epitaxial feature is in a (110) crystal plane.

Forksheet field-effect transistor (FET) devices are provided. A forksheet FET device includes a first FET having a first conductive gate material. The forksheet FET device includes a second FET that is adjacent the first FET and that has the first conductive gate material. Moreover, the forksheet FET device includes a conductive wall that separates the first FET from the second FET. The conductive wall includes a second conductive gate material that is different from the first conductive gate material.

A method of manufacturing an integrated circuit device includes sequentially forming a lower channel stack, an intermediate layer, and an upper channel stack on a substrate, forming a recess space by removing portions of the lower and upper channel stacks, and the intermediate layer, forming, sequentially, an insulating layer, a lower source/drain region and an upper source/drain region in the recess space, removing a sacrificial layer included in the lower and upper channel stacks and the intermediate layer, and forming a lower gate insulating layer on the lower channel stack and an upper gate insulating layer on the upper channel stack, forming a lower gate line on the lower gate insulating layer and an upper gate line on the upper gate insulating layer, and forming a gate isolation structure after the forming of the lower gate line and before the forming of the upper gate line.

A method includes forming a stack of channel layers and sacrificial layers over a substrate, patterning the stack to form a fin-shape structure, and recessing a portion of the fin-shape structure to form a recess. A top surface of the substrate under the recess is covered at least by a bottommost sacrificial layer of the stack. The method also includes forming inner spacers on terminal ends of the sacrificial layers that are above the bottommost sacrificial layer, depositing an undoped layer in the recess, and forming a doped epitaxial feature over the undoped layer. The undoped layer covers terminal ends of a bottommost channel layer of the stack. The doped epitaxial feature covers terminal ends of the channel layers that are above the bottommost channel layer.

A semiconductor structure is provided. The semiconductor structure includes a first set of nanostructures that are stacked vertically and spaced apart from one another and formed in a first well, a source/drain feature adjoining the first set of nanostructures, a first top gate electrode layer above a topmost nanostructure in the first set of nanostructures, and an inner gate electrode layer sandwiched between the nanostructures. A first dimension of the inner gate electrode layer in a first direction is greater than a second dimension of the first top gate electrode layer in the first direction.

Techniques are provided herein to form an integrated circuit having semiconductor devices with low-k inner dielectric spacers between semiconductor bodies (e.g., nanoribbons, nanowires, or nanosheets). The dielectric spacers may include any suitable low-k dielectric material. Additionally, the inner dielectric spacers may be formed after the formation of source or drain regions, which improves the stress profile of the source or drain regions against the semiconductor bodies. In one such example, semiconductor bodies extend in a first direction between source or drain regions and a gate structure extends in a second direction over the semiconductor bodies between the source or drain regions. Inner spacers separate the gate structure from the source or drain regions along the first direction. The inner spacers may include a low-k dielectric material, such as silicon dioxide. In some examples, the inner spacers extend outwards beyond the ends of the semiconductor bodies along the first direction.