A method to form a transistor device with a recessed gate structure is provided. In one embodiment, a gate structure is formed overlying a device region and an isolation structure. The gate structure separates a device doping well along a first direction with a pair of recess regions disposed on opposite sides of the device region in a second direction perpendicular to the first direction. A pair of source/drain regions in is formed the device region on opposite sides of the gate structure. A sidewall spacer is formed extending along sidewalls of the gate structure, where a top surface of the sidewall spacer is substantially flush with the top surface of the gate structure. A resistive protection layer is then formed on the sidewall spacer and covering the pair of recess regions.

The present disclosure provides a semiconductor device and a manufacturing method thereof, and an electronic device including the semiconductor device. The semiconductor device includes: a substrate; an active region including a first source/drain region, a channel region and a second source/drain region stacked sequentially on the substrate and adjacent to each other; a gate stack formed around an outer periphery of the channel region; and spacers formed around the outer periphery of the channel region, respectively between the gate stack and the first source/drain region and between the gate stack and the second source/drain region; wherein the spacers each have a thickness varying in a direction parallel to a top surface of the substrate.

A semiconductor structure includes a stack of semiconductor layers disposed over a substrate, a metal gate stack having a top portion disposed over the stack of semiconductor layers and a bottom portion interleaved with the stack of semiconductor layers, an inner spacer disposed on sidewalls of the bottom portion of the metal gate stack, an air gap enclosed in the inner spacer, and an epitaxial source/drain (S/D) feature disposed over the inner spacer and adjacent to the metal gate stack.

A gate stack can be etched to form a trench extending through the gate stack, the trench removing a portion of the gate stack to separate the gate stack into a first gate stack portion and a second gate stack portion. A dielectric material is deposited in the trench to form a dielectric region, the dielectric region having an air gap in the dielectric material. The air gap may extend upward from beneath the gate stack to an area interposed between the end of the first gate stack portion and the end of the second gate stack portion. Contacts to the first gate stack portion and contacts to the second gate stack portion may be formed which are electrically isolated from each other by the dielectric material and air gap formed therein.

Fin-like field effect transistors (FinFETs) and methods of fabrication thereof are disclosed herein. The FinFETs disclosed herein have gate air spacers integrated into their gate structures. An exemplary transistor includes a fin and a gate structure disposed over the fin between a first epitaxial source/drain feature and a second epitaxial source/drain feature. The gate structure includes a gate electrode, a gate dielectric, and gate air spacers disposed between the gate dielectric and sidewalls of the gate electrode.

A device includes a plurality of fin structures that each protrude vertically upwards out of a substrate and each extend in a first direction in a top view. A gate structure is disposed over the fin structures. The gate structure extends in a second direction in the top view. The second direction is different from the first direction. The fin structures have a fin pitch equal to a sum of: a dimension of one of the fin structures in the second direction and a distance between an adjacent pair of the fin structures in the second direction. An end segment of the gate structure extends beyond an edge of a closest one of the fin structures in the second direction. The end segment has a tapered profile in the top view or is at least 4 times as long as the fin pitch in the second direction.

Semiconductor devices include a stack of vertically arranged channel layers. A gate stack is formed above, between, and around the vertically arranged channel layers. Source and drain regions and source and drain conductive contacts are formed. Inner spacers are formed between the vertically arranged channel layers, each having an inner air gap and a recessed layer formed from a first dielectric material. Outer spacers are formed between the gate stack and the source and drain conductive contacts, each having a second dielectric material that is pinched off to form an outer air gap.

A method for fabricating a semiconductor device includes the steps of: forming a fin-shaped structure on a substrate, forming a gate material layer on the fin-shaped structure, performing an etching process to pattern the gate material layer for forming a gate structure and a silicon residue, performing an ashing process on the silicon residue, and then performing a cleaning process to transform the silicon residue into a polymer stop layer on a top surface and sidewalls of the fin-shaped structure.

A method of manufacturing a semiconductor device may include forming a hardmask layer on gate lines and intergate insulating portions alternately arranged; respectively forming mandrel lines on regions of the hardmask layer, corresponding to every other one of the intergate insulating portions; conformally forming a spacer material layer, having a thickness corresponding to a width of the gate lines, on the hardmask layer; forming a mandrel material layer on the spacer material layer; removing a portion of the mandrel material layer to expose portions of the spacer material layer on an upper surface and a side surface of the mandrel line; removing the exposed portions of the spacer material layer to provide the mandrel lines and stacked mandrel patterns; and forming an opening in the hardmask layer, which exposes a gate-cut region of the gate lines, using the mandrel lines and the stacked mandrel patterns as a mask.

Self-aligned gate cutting techniques are disclosed herein that provide dielectric gate isolation fins for isolating gates of multigate devices from one another. An exemplary device includes a first multigate device having first source/drain features and a first metal gate that surrounds a first channel layer and a second multigate device having second source/drain features and a second metal gate that surrounds a second channel layer. A dielectric gate isolation fin separates the first metal gate from the second metal gate. The dielectric gate isolation fin includes a first dielectric layer having a first dielectric constant and a second dielectric layer having a second dielectric constant disposed over the first dielectric layer. The second dielectric constant is greater than the first dielectric constant. The first metal gate and the second metal gate physically contact the first channel layer and the second channel layer, respectively, and the dielectric gate isolation fin.