Semiconductor devices and methods are provided. A semiconductor device according to the present disclosure includes a first transistor in a first area and a second transistor in a second area. The first transistor includes a first gate structure extending lengthwise along a first direction, and a first gate spacer, a second gate spacer, and a third gate spacer over sidewalls of the first gate structure. The second transistor includes a second gate structure extending lengthwise along the first direction, and the first gate spacer and the third gate spacer over sidewalls of the second gate structure. The first gate spacer, the second gate spacer and the third gate spacer are of different compositions and the third gate spacer is directly on the first gate spacer in the second area.

Epitaxial regions may be formed in specific locations on a semiconductor wafer with specific asymmetric properties such as slope or tilt direction, slope or tilt angle, and/or other asymmetric properties. The asymmetric epitaxial regions may be formed using various plasma-based fin structure etching techniques described herein. The specific asymmetric properties may increase metal landing coverage areas in particular locations on the semiconductor wafer (e.g., that are optimized for particular locations on the semiconductor substrate) to reduce the contact resistance between the epitaxial regions and associated conductive structures that are formed to the epitaxial regions. This increases semiconductor device performance, decreases the rate and/or likelihood of defect formation, and/or increases semiconductor device yield, among other examples.

In an example, a method includes depositing a first sidewall spacer layer over a substrate having a layer stack including alternating layers of a nanosheet and a sacrificial layer, and a dummy gate formed over the layer stack, the first sidewall spacer layer formed over the dummy gate. The method includes depositing a metal-containing liner over the first sidewall spacer layer; forming a first sidewall spacer along the dummy gate by anisotropically etching the metal-containing liner and the first sidewall spacer layer; performing an anisotropic etch back process to form a plurality of vertical recesses in the layer stack; laterally etching the layer stack and form a plurality of lateral recesses between adjacent nanosheets; depositing a second sidewall spacer layer to fill the plurality of lateral recesses; and etching a portion of the second sidewall spacer layer to expose tips of the nanosheet layers.

An integrated circuit includes a nanosheet transistor having a plurality of stacked channels, a gate electrode surrounding the stacked channels, a source/drain region, and a source/drain contact. The integrated circuit includes a first dielectric layer between the gate metal and the source/drain contact, a second dielectric layer on the first dielectric layer, and a cap metal on the first gate metal and on a hybrid fin structure. The second dielectric layer is on the hybrid fin structure between the cap metal and the source/drain contact.

A method for forming a semiconductor device structure is provided. The semiconductor device includes forming nanowire structures stacked over a substrate and spaced apart from one another, and forming a dielectric material surrounding the nanowire structures. The dielectric material has a first nitrogen concentration. The method also includes treating the dielectric material to form a treated portion. The treated portion of the dielectric material has a second nitrogen concentration that is greater than the first nitrogen concentration. The method also includes removing the treating portion of the dielectric material, thereby remaining an untreated portion of the dielectric material as inner spacer layers; and forming the gate stack surrounding nanowire structures and between the inner spacer layers.

A method of forming a power rail to semiconductor devices comprising removing a portion of the gate structure forming a gate cut trench separating a first active region of fin structures from a second active region of fin structures. A conformal etch stop layer is formed in the gate cut trench. A fill material is formed on the conformal etch stop layer filling at least a portion of the gate cut trench. The fill material has a composition that is etched selectively to the conformal etch stop layer. A power rail is formed in the gate cut trench. The conformal etch stop layer obstructs lateral etching during forming the power rail to substantially eliminate power rail to gate structure shorting.

Disclosed are semiconductor devices and methods of fabricating the same. The method comprises sequentially stacking a lower sacrificial layer and an upper sacrificial layer on a substrate, patterning the upper sacrificial layer to form a first upper sacrificial pattern and a second upper sacrificial pattern, forming a first upper spacer and a second upper spacer on sidewalls of the first upper sacrificial pattern and a second upper sacrificial pattern, respectively, using the first and second upper spacers as an etching mask to pattern the lower sacrificial layer to form a plurality of lower sacrificial patterns, forming a plurality of lower spacers on sidewalls of the lower sacrificial patterns, and using the lower spacers as an etching mask to pattern the substrate. The first and second upper spacers are connected to each other.

A method includes providing dummy gate structures disposed over a device region and over an isolation region adjacent the active region, first gate spacers disposed along sidewalls of the dummy gate structures in the active region, and second gate spacers disposed along sidewalls of the dummy gate structures in the isolation region, removing top portions of the second, but not the first gate spacers, forming a first dielectric layer over the first gate spacers and remaining portions of the second gate spacers, replacing the dummy gate structures with metal gate structures after the forming of the first dielectric layer, removing the first gate spacers after the replacing of the dummy gate structures, and forming a second dielectric layer over top surfaces of the metal gate structures and of the first dielectric layer.

A method for fabricating a semiconductor device includes forming a trench in a substrate, forming a gate dielectric layer on a surface of the trench, forming a lower gate, which partially fills the trench, over the gate dielectric layer, forming a low work function layer over the lower gate, forming a spacer over the low work function layer, etching the low work function layer to be self-aligned with the spacer in order to form vertical gate on both upper edges of the lower gate, and forming an upper gate over the lower gate between inner sidewalls of the vertical gate.

Semiconductor devices is provided. The semiconductor device includes a semiconductor substrate having a first region and an adjacent second region; a plurality of adjacent first fins in the first region of the semiconductor substrate; a plurality of adjacent second fins in the second region of the semiconductor substrate; a first type of fin sidewall spacers; a second type of fin sidewall spacers; first doped layers formed between adjacent first type of fin sidewall spacers in the first region; and second doped layers formed between adjacent first type of fin sidewall spacers in the second region.