A semiconductor device with an isolation structure and a method of fabricating the same are disclosed. The semiconductor device includes first and second fin structures disposed on a substrate and first and second pairs of gate structures disposed on the first and second fin structures. The first end surfaces of the first pair of gate structures face second end surfaces of the second pair of gate structure. The first and second end surfaces of the first and second pair of gate structures are in physical contact with first and second sidewalls of the isolation structure, respectively. The semiconductor device further includes an isolation structure interposed between the first and second pairs of gate structures. An aspect ratio of the isolation structure is smaller than a combined aspect ratio of the first pair of gate structures.

A method includes forming a semiconductor fin protruding higher than top surfaces of isolation regions. The isolation regions extend into a semiconductor substrate. The method further includes etching a portion of the semiconductor fin to form a trench, filling the trench with a first dielectric material, wherein the first dielectric material has a first bandgap, and performing a recessing process to recess the first dielectric material. A recess is formed between opposing portions of the isolation regions. The recess is filled with a second dielectric material. The first dielectric material and the second dielectric material in combination form an additional isolation region. The second dielectric material has a second bandgap smaller than the first bandgap.

A semiconductor device is disclosed. The semiconductor device includes a fin-based structure formed on a substrate. The semiconductor device includes a plurality of first nanosheets, vertically spaced apart from one another, that are formed on the substrate. The semiconductor device includes a first source/drain (S/D) region electrically coupled to a first end of the fin-based structure. The semiconductor device includes a second S/D region electrically coupled to both of a second end of the fin-based structure and a first end of the plurality of first nanosheets. The semiconductor device includes a third S/D region electrically coupled to a second end of the plurality of first nanosheets. The fin-based structure has a first crystal lattice direction and the plurality of first nanosheets have a second crystal lattice direction, which is different from the first crystal lattice direction.

Stacked FET devices having wrap-around contacts to optimize contact resistance and techniques for formation thereof are provided. In one aspect, a stacked FET device includes: a bottom-level FET(s) on a substrate; lower contact vias present in an ILD disposed over the bottom-level FET(s); a top-level FET(s) present over the lower contact vias; and top-level FET source/drain contacts that wrap-around source/drain regions of the top-level FET(s), wherein the lower contact vias connect the top-level FET source/drain contacts to source/drain regions of the bottom-level FET(s). When not vertically aligned, a local interconnect can be used to connect a given one of the lower contact vias to a given one of the top-level FET source/drain contacts. A method of forming a stacked FET device is also provided.

Backside interconnect structures having reduced critical dimensions for semiconductor devices and methods of forming the same are disclosed. In an embodiment, a device includes a first transistor structure over a front-side of a substrate; a first backside interconnect structure over a backside of the substrate, the first backside interconnect structure including first conductive features having tapered sidewalls with widths that narrow in a direction away from the substrate; a power rail extending through the substrate, the power rail being electrically coupled to the first conductive features; and a first source/drain contact extending from the power rail to a first source/drain region of the first transistor structure.

A semiconductor device includes a substrate including a first region and a second region, a first active pattern on the first region, a first gate structure having a first width in the first direction, on the first active pattern, a first epitaxial pattern disposed in the first active pattern on a side surface of the first gate structure, a second active pattern on the second region, a second gate structure having a second width greater than the first width in the first direction, on the second active pattern and a second epitaxial pattern disposed in the second active pattern on a side surface of the second gate structure. Each of the first epitaxial pattern and the second epitaxial pattern includes silicon germanium (SiGe), and a first Ge concentration of the first epitaxial pattern is lower than a second Ge concentration of the second epitaxial pattern.

A device includes a substrate, an isolation structure over the substrate, and two fins extending from the substrate and above the isolation structure. Two source/drain structures are over the two fins respectively and being side by side along a first direction generally perpendicular to a lengthwise direction of the two fins from a top view . Each of the two source/drain structures has a near-vertical side, the two near-vertical sides facing each other along the first direction. A contact etch stop layer (CESL) is disposed on at least a lower portion of the near-vertical side of each of the two source/drain structures. And two contacts are disposed over the two source/drain structures, respectively, and over the CESL.

In an embodiment, a structure includes: a contact etch stop layer (CESL) over a substrate; a fin extending through the CESL; an epitaxial source/drain region in the fin, the epitaxial source/drain region extending through the CESL; a silicide contacting upper facets of the epitaxial source/drain region; a source/drain contact contacting the silicide, lower facets of the epitaxial source/drain region, and a first surface of the CESL; and an inter-layer dielectric (ILD) layer surrounding the source/drain contact, the ILD layer contacting the first surface of the CESL.

According to one example, a method includes forming a first set of fin structures on a substrate, forming a sacrificial material between fin structures within the first set of fin structures, forming a dummy gate with a planar bottom surface over the fin structures and the sacrificial material, forming sidewall structures on the dummy gate, laterally etching the sacrificial material underneath the sidewall structures, depositing a lower sidewall structure where the sacrificial material was removed, removing the dummy gate, removing the sacrificial material, and forming a real gate over the fin structures.

A semiconductor device according to the present disclosure includes a first gate structure and a second gate structure aligned along a direction, a first metal layer disposed over the first gate structure, a second metal layer disposed over the second gate structure, and a gate isolation structure extending between the first gate structure and the second gate structure as well as between the first metal layer and the second metal layer.