Device-level interconnects having high thermal stability for stacked device structures are disclosed herein. An exemplary stacked semiconductor structure includes an upper source/drain contact disposed on an upper epitaxial source/drain, a lower source/drain contact disposed on a lower epitaxial source/drain, and a source/drain via connected to the upper source/drain contact and the lower source/drain contact. The source/drain via is disposed on the upper source/drain contact, the source/drain via extends below the upper source/drain contact, and the source/drain via includes ruthenium and aluminum. In some embodiments, the source/drain via includes a ruthenium plug wrapped by an aluminum liner. In some embodiments, the source/drain via includes a ruthenium aluminide plug. In some embodiments, the source/drain via includes a ruthenium plug wrapped by a ruthenium aluminide liner. In some embodiments, the source/drain via extends below a top of the lower epitaxial source/drain.

Semiconductor structures and methods of forming the same are provided. In an embodiment, an exemplary semiconductor structure includes a first transistor. The first transistor includes a first gate structure wrapping around a plurality of first nanostructures disposed over a substrate, a first source/drain feature electrically coupled to a topmost nanostructure of the plurality of first nanostructures and isolated from a bottommost nanostructure of the plurality of first nanostructures by a first dielectric layer, and a first semiconductor layer disposed between the substrate and the first source/drain feature, wherein the first source/drain feature is in direct contact with a top surface of the first semiconductor layer.

A method includes forming a stack of nanostructures over a substrate; forming a recess in the substrate adjacent the stack of nanostructures, wherein the recess exposes sidewalls of the stack of nanostructures; depositing a continuous semiconductor seed layer in the recess and extending along the sidewalls of the stack of nanostructures; epitaxially growing a source/drain region on the semiconductor seed layer; after epitaxially growing the source/drain region, forming inner spacers between adjacent nanostructures of the stack of nanostructures; and forming a gate structure between adjacent nanostructures of the stack of nanostructures.

Provided is a semiconductor device which includes: a substrate; a channel structure on the substrate; a source/drain pattern connected to the channel structure; a gate structure on the channel structure; an inner spacer structure comprising an inner spacer between the source/drain pattern and the gate structure, and an inner spacer residue connected to the inner spacer structure; and an inner isolation structure between the inner spacer residue and a bottom surface of the source/drain pattern.

An example semiconductor device includes a lower wiring layer including lower wiring lines, an upper wiring layer including upper wiring lines, and a power gating cell between the lower and upper wiring layers. The power gating cell includes a first active region on a substrate and including first and second lower source/drain patterns and a first channel pattern connecting the first and second lower source/drain patterns with each other, a second active region on the first active region and including first and second upper source/drain patterns, and a power gate electrode surrounding the first channel pattern and extending in a first direction parallel to a top surface of the substrate. The lower wiring layer includes a global power line connected with the first lower source/drain pattern and a local power line connected with the second lower source/drain pattern.

A method includes forming Complementary Field-Effect Transistors including a lower transistor comprising a lower source/drain region, and an upper transistor including an upper source/drain region. An upper dielectric layer over the upper source/drain region and a lower dielectric layer under the upper source/drain region are etched to form an opening. A sidewall of the upper source/drain region and a top surface of the lower source/drain region are exposed to the opening. An epitaxy process is performed to form a first semiconductor layer on the sidewall of the upper source/drain region, and a second semiconductor layer on the top surface of the lower source/drain region. The first semiconductor layer is then removed, a contact plug is formed in the opening to electrically connects the upper source/drain region to the second semiconductor layer and the lower source/drain region.

Embodiments of the present disclosure provide a semiconductor device structure and methods of forming the same. The method includes forming a fin structure from a substrate, and the fin structure includes a plurality of semiconductor layers. The method further includes depositing a gate dielectric layer around a portion of each semiconductor layer of the plurality of semiconductor layers, depositing an adhesion layer on the gate dielectric layer, and the adhesion layer surrounds the portion of each semiconductor layer of the plurality of semiconductor layers. The method further includes depositing a fluorine-containing layer on the adhesion layer, and the fluorine-containing layer surrounds the portion of each semiconductor layer of the plurality of semiconductor layers. The method further includes performing an annealing process on the fluorine-containing layer, removing the fluorine-containing layer and the adhesion layer, and forming a gate electrode layer on the gate dielectric layer.

A method of forming a complementary field-effect transistor (CFET) device includes: forming a plurality of channel regions stacked vertically over a fin; forming an isolation structure between a first subset of the plurality of channel regions and a second subset of the plurality of channel regions; forming a gate dielectric material around the plurality of channel regions and the isolation structure; forming a work function material around the gate dielectric material; forming a silicon-containing passivation layer around the work function material; after forming the silicon-containing passivation layer, removing a first portion of the silicon-containing passivation layer disposed around the first subset of the plurality of channel regions and keeping a second portion of the silicon-containing passivation layer disposed around the second subset of the plurality of channel regions; and after removing the first portion of the silicon-containing passivation layer, forming a gate fill material around the plurality of channel regions.

Method to form low-contact-resistance contacts to source/drain features are provided. A method of the present disclosure includes receiving a workpiece including an opening that exposes a surface of an n-type source/drain feature and a surface of a p-type source/drain feature, selectively depositing a first silicide layer on the surface of the p-type source/drain feature while the surface of the n-type source/drain feature is substantially free of the first silicide layer, depositing a metal layer on the first silicide layer and the surface of the n-type source/drain feature, and depositing a second silicide layer over the metal layer. The selectively depositing includes passivating the surface of the surface of the n-type source/drain features with a self-assembly layer, selectively depositing the first silicide layer on the surface of the p-type source/drain feature, and removing the self-assembly layer.

Provided is a semiconductor device which includes: a substrate; a channel structure on the substrate; a source/drain pattern connected to the channel structure; a gate structure on the channel structure; an inner spacer structure comprising an inner spacer between the source/drain pattern and the gate structure, and an inner spacer residue connected to the inner spacer structure; and an inner isolation structure between the inner spacer residue and a bottom surface of the source/drain pattern.