A semiconductor device may include first and second active regions on a substrate, first and second active patterns on the first and second active regions, first and second source/drain patterns on the first and second active patterns, first and second silicide patterns on the first and second source/drain patterns, and first and second active contacts coupled to the first and second source/drain patterns. A lowermost portion of the first active contact is at a level higher than that of a lowermost portion of the second active contact. A thickness of the first silicide pattern is greater than that of the second silicide pattern.

Nanostructure field-effect transistors (NSFETs) including isolation layers formed between epitaxial source/drain regions and semiconductor substrates and methods of forming the same are disclosed. In an embodiment, a semiconductor device includes a semiconductor substrate; a gate stack over the semiconductor substrate, the gate stack including a gate electrode and a gate dielectric layer; a first epitaxial source/drain region adjacent the gate stack; and a high-k dielectric layer extending between the semiconductor substrate and the first epitaxial source/drain region, the high-k dielectric layer contacting the first epitaxial source/drain region, the gate dielectric layer and the high-k dielectric layer including the same material.

A semiconductor device includes a channel pattern including a first semiconductor pattern and a second semiconductor pattern, which are sequentially stacked on a substrate, and a gate electrode that extends in a first direction and crosses the channel pattern. The gate electrode includes a first portion interposed between the substrate and the first semiconductor pattern and a second portion interposed between the first and second semiconductor patterns. A maximum width in a second direction of the first portion is greater than a maximum width in the second direction of the second portion, and a maximum length in the second direction of the second semiconductor pattern is less than a maximum length in the second direction of the first semiconductor pattern.

A semiconductor device and a method of forming the same are provided. A method includes forming a fin structure on a substrate. The fin structure includes a plurality of first nanostructures and a plurality of second nanostructures alternately stacked. A dummy gate is formed along sidewalls and a top surface of the fin structure. A portion of the fin structure exposed by the dummy gate is recessed to form a first recess. An epitaxial source/drain region is formed in the first recess. Dopant atoms within the epitaxial source/drain region are driven into the plurality of second nanostructures. The dummy gate and the plurality of first nanostructures are removed. A replacement gate is formed wrapping around the plurality of second nanostructures.

Nanostructure field-effect transistors (NSFETs) including isolation layers formed between epitaxial source/drain regions and semiconductor substrates and methods of forming the same are disclosed. In an embodiment, a semiconductor device includes a semiconductor substrate; a gate stack over the semiconductor substrate, the gate stack including a gate electrode and a gate dielectric layer; a first epitaxial source/drain region adjacent the gate stack; and a high-k dielectric layer extending between the semiconductor substrate and the first epitaxial source/drain region, the high-k dielectric layer contacting the first epitaxial source/drain region, the gate dielectric layer and the high-k dielectric layer including the same material.

A semiconductor device structure is provided. The semiconductor device structure includes a substrate and a first nanostructure over the substrate. The semiconductor device structure also includes a gate stack over the substrate and surrounding the first nanostructure and a first source/drain layer surrounding the first nanostructure and adjacent to the gate stack. The semiconductor device structure further includes a contact structure surrounding the first source/drain layer. A first portion of the contact structure is between the first nanostructure and the substrate, and the first portion of the contact structure has a first curved top surface facing the first nanostructure.

A semiconductor device and a method of forming the same are provided. A method includes forming a fin structure on a substrate. The fin structure includes a plurality of first nanostructures and a plurality of second nanostructures alternately stacked. A dummy gate is formed along sidewalls and a top surface of the fin structure. A portion of the fin structure exposed by the dummy gate is recessed to form a first recess. An epitaxial source/drain region is formed in the first recess. Dopant atoms within the epitaxial source/drain region are driven into the plurality of second nanostructures. The dummy gate and the plurality of first nanostructures are removed. A replacement gate is formed wrapping around the plurality of second nanostructures.

A semiconductor device may include first and second active regions on a substrate, first and second active patterns on the first and second active regions, first and second source/drain patterns on the first and second active patterns, first and second silicide patterns on the first and second source/drain patterns, and first and second active contacts coupled to the first and second source/drain patterns. A lowermost portion of the first active contact is at a level higher than that of a lowermost portion of the second active contact. A thickness of the first silicide pattern is greater than that of the second silicide pattern.

Embodiments disclosed herein include semiconductor devices and methods of forming such semiconductor devices. In an embodiment, a semiconductor device comprises a semiconductor channel, a source region adjacent to the semiconductor channel, and a drain region adjacent to the semiconductor channel. In an embodiment, the source region and the drain region each comprise a trench, a conformal silicide lining the trench, and a binary metallic alloy filling the trench.

A semiconductor device includes a substrate, a plurality of insulators, a liner structure and a gate stack. The substrate has fins and trenches in between the fins. The insulators are disposed within the trenches of the substrate. The liner structure is disposed on the plurality of insulators and across the fins, wherein the liner structure comprises sidewall portions and a cap portion, the sidewall portions is covering sidewalls of the fins, the cap portion is covering a top surface of the fins and joined with the sidewall portions, and a maximum thickness T.sub.1 of the cap portion is greater than a thickness T.sub.2 of the sidewall portions. The gate stack is disposed on the liner structure and across the fins.