Semiconductor structures and methods of forming the same are provided. A method according to an embodiment includes receiving a workpiece comprising a first semiconductor element and a second semiconductor element, and a dielectric fin disposed between the first semiconductor element and the second semiconductor element. The method also includes forming a masking layer directly over the dielectric fin, etching the first semiconductor element and the second semiconductor element to form a first recess and a second recess, and forming a first source/drain feature and a second source/drain feature in the first recess and the second recess, respectively. By employing a masking layer and patterning the masking layer to have different widths, a parasitic resistance and a parasitic capacitance of the semiconductor structure may be adjusted accordingly, and undesirably bridging between two adjacent epitaxial source/drain features may be prevented.

A method for making a semiconductor device includes forming a first fin structure, a second fin structure, and a third fin structure over a substrate. The first through third fin structures all extend along a first lateral direction, and the second fin structure is disposed between the first and third fin structures. The method includes forming a mold by filling up trenches between neighboring ones of the first through third fin structures with a first dielectric material. The method includes cutting the second fin structure by removing an upper portion of the second fin structure. The method includes replacing the upper portion of the second fin structure with a second dielectric material to form a dielectric cut structure. The method includes recessing the mold to expose upper portions of the first fin structure and the third fin structure, respectively.

A semiconductor structure includes first and second source/drain (S/D) features, one or more channel layers connecting the first and the second S/D features, a high-k metal gate engaging the one or more channel layers, an isolation structure, a power rail under the isolation structure, and a via structure extending through the isolation structure and electrically connecting the first S/D feature and the power rail. At least a portion of the isolation structure is under the first and the second S/D features. In a cross-section that extends through the first S/D feature and perpendicular to a direction from the first S/D feature to the second S/D feature along the one or more channel layers, the via structure extends into a gap vertically between the first S/D feature and the isolation structure.

A vertical, fin-based field effect transistor (FinFET) device includes an array of individual FinFET cells. The array includes a plurality of rows and columns of separated fins. Each of the separated fins is in electrical communication with a source contact. The vertical FinFET device also includes one or more rows of first inactive fins disposed on a first set of sides of the array of individual FinFET cells, one or more columns of second inactive fins disposed on a second set of sides of the array of individual FinFET cells, and a gate region surrounding the individual FinFET cells of the array of individual FinFET cells, the first inactive fins, and the second inactive fins.

A semiconductor structure includes an isolation structure; first and second source/drain (S/D) features over the isolation structure, defining a first direction from the first S/D feature to the second S/D feature from a top view; one or more channel layers connecting the first and the second S/D features; a gate structure between the first and the second S/D features and engaging each of the one or more channel layers; and a via structure under the first S/D feature and electrically connecting to the first S/D feature. In a cross-sectional view perpendicular to the first direction, the via structure has a profile that widens and then narrows along a bottom-up direction.

A semiconductor structure includes a semiconductor substrate; fin active regions protruded above the semiconductor substrate; and a gate stack disposed on the fin active regions; wherein the gate stack includes a high-k dielectric material layer, and various metal layers disposed on the high-k dielectric material layer. The gate stack has an uneven profile in a sectional view with a first dimension D.sub.1 at a top surface, a second dimension D.sub.2 at a bottom surface, and a third dimension D.sub.3 at a location between the top surface and the bottom surface, and wherein each of D.sub.1 and D.sub.2 is greater than D.sub.3.

A semiconductor device includes a silicon substrate and a fin formed above the substrate. The fin provides active regions for two devices, such as gate-all-around transistors. The semiconductor device also includes a fin-insulating structure positioned to electrically isolate the active regions for the two devices. The fin-insulating structure is formed in a trench, with a first portion adjacent the fin and a second portion below the fin and extending into the substrate. The fin-insulating structure includes an oxide liner in the second portion of the trench, but not the first portion. The fin-insulating structure is further filled with an insulating material such as silicon nitride.

A semiconductor device comprising a semiconductor channel, an epitaxial structure coupled to the semiconductor channel, and a gate structure electrically coupled to the semiconductor channel. The semiconductor device further comprises a first interconnect structure electrically coupled to the epitaxial structure and a dielectric layer that contains nitrogen. The dielectric layer comprises a first portion protruding from a nitrogen-containing dielectric capping layer that overlays either the gate structure or the first interconnect structure.

A semiconductor structure includes fins protruding from a substrate and separated by a dielectric layer, each semiconductor fin including a plurality of semiconductor layers, source/drain (S/D) features disposed in the semiconductor fins, a first metal gate stack and a second metal gate stack disposed over the semiconductor fins and adjacent to the S/D features, where the first and the second metal gate stacks each include a top portion and a bottom portion disposed below the top portion, and where the bottom portion is interleaved with the semiconductor layers, and an isolation feature disposed on the dielectric layer and in contact with a sidewall surface of each of the first and the second metal gate stacks, where the isolation feature protrudes from the top portion of the first and the second metal gate stack, and where the isolation feature includes two compositionally different dielectric layers.

A method for manufacturing an integrated circuit device is provided. The method includes forming first, second, and third semiconductor fins over a semiconductor substrate, in which the second semiconductor fin is between the first and third semiconductor fins; forming first and second fin sidewall spacers respectively on a sidewall of a first portion of the first semiconductor fin and a sidewall of a first portion of the second semiconductor fin, wherein the first and second fin sidewall spacers are between the first and second semiconductor fins; recessing the first portions of the first and second semiconductor fins and a first portion of the third semiconductor fin; and forming first to third epitaxial features respectively on the recessed portions of the first to third semiconductor fins, wherein the second epitaxial feature is spaced apart from the first epitaxial feature and merged with the third epitaxial feature.