Integrated circuit devices and methods of forming the same are provided. The methods may include sequentially forming an underlying mask layer and a preliminary first mask layer on a substrate, forming a first mask structure by removing a portion of the preliminary first mask layer, and then forming a preliminary second mask layer. The preliminary second mask layer may enclose the first mask structure in a plan view. The methods may also include forming a second mask structure by removing a portion of the preliminary second mask layer and forming a vertical channel region including a portion of the substrate by sequentially etching the underlying mask layer and the substrate. The second mask structure may be connected to the first mask structure, and etching the underlying mask layer may be performed using the first and the second mask structures as an etch mask.

A semiconductor includes an active pattern with a lower pattern and sheet patterns spaced apart from the lower pattern in a first direction, a source/drain pattern on the lower pattern, the source/drain pattern being in contact with the sheet patterns, and gate structures on opposite sides of the source/drain pattern, the gate structures being spaced apart from each other along a second direction and including gate electrodes that surround the sheet patterns, wherein the source/drain pattern includes a first epitaxial region having at least one of antimony and bismuth, the first epitaxial region having a bottom part in contact with the lower pattern, but not with the sheet patterns, and a thickness of the bottom part increasing and decreasing away from the gate structures in the second direction, and a second epitaxial region on the first epitaxial region, the second epitaxial region including phosphorus.

A method of forming a semiconductor device includes: forming a dummy gate structure over a fin structure that protrudes above a substrate, where the fin structure includes a fin and a layer stack over the fin, where the layer stack comprises alternating layers of a first semiconductor material and a second semiconductor material; forming openings in the fin structure on opposing sides of the dummy gate structure, where the openings exposes first portions of the first semiconductor material and second portions of the second semiconductor material; recessing the exposed first portions of the first semiconductor material to form sidewall recesses in the first semiconductor material; lining the sidewall recesses with a first dielectric material; depositing a second dielectric material in the sidewall recesses on the first dielectric material; after depositing the second dielectric material, annealing the second dielectric material; and after the annealing, forming source/drain regions in the openings.

In a method of manufacturing a semiconductor device, first and second fin structures are formed over a substrate, an isolation insulating layer is formed over the substrate, a gate structure is formed over channel regions of the first and second fin structures, source/drain regions of the first and second fin structure are recessed, and an epitaxial source/drain structure is formed over the recessed first and second fin structures. The epitaxial source/drain structure is a merged structure having a merger point, and a height of a bottom of the merger point from an upper surface of the isolation insulating layer is 50% or more of a height of the channel regions of the first and second fin structures from the upper surface of the isolation insulating layer.

A semiconductor device includes a first semiconductor well. The semiconductor device includes a channel structure disposed above the first semiconductor well and extending along a first lateral direction. The semiconductor device includes a gate structure extending along a second lateral direction and straddling the channel structure. The semiconductor device includes a first epitaxial structure disposed on a first side of the channel structure. The semiconductor device includes a second epitaxial structure disposed on a second side of the channel structure, the first side and second side opposite to each other in the first lateral direction. The first epitaxial structure is electrically coupled to the first semiconductor well with a second semiconductor well in the first semiconductor well, and the second epitaxial structure is electrically isolated from the first semiconductor well with a dielectric layer.

A method of forming a semiconductor device includes: forming a fin structure protruding above a substrate, where the fin structure includes a fin and a layer stack over the fin, the layer stack comprising alternating layers of a first semiconductor material and a second semiconductor material; forming a first dummy gate structure and a second dummy gate structure over the fin structure; forming an opening in the fin structure between the first dummy gate structure and the second dummy gate structure; converting an upper layer of the fin exposed at a bottom of the opening into a seed layer by performing an implantation process; selectively depositing a dielectric layer over the seed layer at the bottom of the opening; and selectively growing a source/drain material on opposing sidewalls of the second semiconductor material exposed by the opening.

Semiconductor devices including air spacers formed in a backside interconnect structure and methods of forming the same are disclosed. In an embodiment, a device includes a first transistor structure; a front-side interconnect structure on a front-side of the first transistor structure; and a backside interconnect structure on a backside of the first transistor structure, the backside interconnect structure including a first dielectric layer on the backside of the first transistor structure; a first via extending through the first dielectric layer, the first via being electrically coupled to a source/drain region of the first transistor structure; a first conductive line electrically coupled to the first via; and an air spacer adjacent the first conductive line in a direction parallel to a backside surface of the first dielectric layer.

A semiconductor device includes: a pair of wire patterns configured to extend in a first direction and formed on a substrate to be spaced apart from each other in a second direction, the pair of wire patterns disposed closest to each other in the second direction; a gate electrode configured to extend in the second direction on the substrate, the gate electrode configured to surround the wire patterns; and first isolation layers configured to extend in the first direction between the substrate and the gate electrode and formed to be spaced apart from each other in the second direction, the first isolation layers overlapping the pair of wire patterns in a third direction perpendicular to the first and second directions.

A semiconductor device with isolation structures and a method of fabricating the same are disclosed. The method includes forming a fin structure on a substrate forming a superlattice structure with first and second nanostructured layers on the fin structure, forming a source/drain (S/D) opening in the superlattice structure, forming an isolation opening in the fin structure and below the S/D opening, forming a first isolation layer in the isolation opening, selectively forming an oxide layer on sidewalls of the S/D opening, selectively forming an inhibitor layer on the oxide layer, selectively depositing a second isolation layer on the first isolation layer, and forming S/D regions in the S/D opening on the second isolation layer.

A forksheet transistor device includes a dual dielectric pillar that includes a first dielectric and a second dielectric that is different from the first dielectric. The dual dielectric pillar physically separates pFET elements from nFET elements. For example, the first dielectric physically separates a pFET gate from a nFET gate while the second dielectric physically separates a pFET source/drain region from a nFET source drain region. When it is advantageous to electrically connect the pFET gate and the nFET gate, the first dielectric may be etched selective to the second dielectric to form a gate connector trench within the dual dielectric pillar. Subsequently, an electrically conductive gate connector strap may be formed within the gate connector trench to electrically connect the pFET gate and the nFET gate.